Skip to main content
PMC home page
European Journal of Psychotraumatology logoLink to European Journal of Psychotraumatology
. 2020 Mar 9;11(1):1709709. doi: 10.1080/20008198.2019.1709709

Dropout from psychological therapies for post-traumatic stress disorder (PTSD) in adults: systematic review and meta-analysis

El abandono de las terapias psicológicas para el trastorno de estrés postraumático (TEPT) en adultos: Una revisión sistemática y meta-análisis

成人创伤后应激障碍（PTSD）心理治疗的中途退出：系统综述和元分析

Catrin Lewis a,✉, Neil P Roberts a,b,c, Samuel Gibson a, Jonathan I Bisson a
PMCID: PMC7144189  PMID: 32284816

ABSTRACT

Background: Despite the established efficacy of psychological therapies for post-traumatic stress disorder (PTSD) there has been little systematic exploration of dropout rates.

Objective: To ascertain rates of dropout across different modalities of psychological therapy for PTSD and to explore potential sources of heterogeneity.

Method: A systematic review of dropout rates from randomized controlled trials (RCTs) of psychological therapies was conducted. The pooled rate of dropout from psychological therapies was estimated and reasons for heterogeneity explored using meta-regression.

Results:: The pooled rate of dropout from RCTs of psychological therapies for PTSD was 16% (95% CI 14–18%). There was evidence of substantial heterogeneity across studies. We found evidence that psychological therapies with a trauma-focus were significantly associated with greater dropout. There was no evidence of greater dropout from therapies delivered in a group format; from studies that recruited participants from clinical services rather than via advertisements; that included only military personnel/veterans; that were limited to participants traumatized by sexual traumas; that included a higher proportion of female participants; or from studies with a lower proportion of participants who were university educated.

Conclusions: Dropout rates from recommended psychological therapies for PTSD are high and this appears to be particularly true of interventions with a trauma focus. There is a need to further explore the reasons for dropout and to look at ways of increasing treatment retention.

KEYWORDS: Post-traumatic stress disorder, trauma, psychological, therapy, dropout, review

1. Introduction

Post-Traumatic Stress Disorder (PTSD) is a debilitating psychiatric disorder with a lifetime prevalence of approximately 8% (Kessler, 2000). In addition to the requirement of exposure to a major traumatic event, the diagnostic criteria for PTSD specify the presence of symptoms including re-experiencing the traumatic event; avoiding reminders of the trauma; alterations in arousal and reactivity; and changes in cognition and mood (American Psychiatric Association, 2013).

Despite decades of research converging on support for the efficacy of psychological therapy for PTSD (Bisson, Roberts, Andrew, Cooper, & Lewis, 2013; Bradley, Greene, Russ, Dutra, & Westen, 2005; Jonas et al., 2013), we know remarkably little regarding dropout from these interventions (Foa et al., 2005; Resick, Nishith, Weaver, Astin, & Feuer, 2002; Schnurr et al., 2007; Schottenbauer, Glass, Arnkoff, Tendick, & Gray, 2008). Many psychological therapies have been applied to the treatment of PTSD and these have fundamentally different components and proposed active ingredients (Foa, Keane, Friedman, & Cohen, 2008; Schnyder et al., 2015). It follows that these variations may have some influence on differential rates of dropout. Despite this likelihood, there have been few attempts to systematically determine dropout rates from the psychological therapies commonly applied to the treatment of PTSD.

Among the evidence-based therapies for PTSD, a major distinction can be drawn between the therapies that focus on the traumatic event and those that aim to reduce traumatic stress symptoms without directly targeting the trauma memory or related thoughts, with the strongest evidence for the effect of those with a trauma-focus (Bisson et al., 2013; Bradley et al., 2005; Jonas et al., 2013). Trauma-focused Cognitive Behaviour Therapy (CBT) and Eye Movement Desensitization and Reprocessing (EMDR) are currently recommended as first-line interventions for PTSD (American Psychological Association, 2017; International Society of Traumatic Stress Studies (ISTSS), 2018; National Institute for Health and Care Excellence (NICE), 2018). These trauma-focused psychological therapies rely on confrontation of traumatic images, which can be difficult to tolerate and may result in the potential for greater dropout (Pitman et al., 1991; Tarrier et al., 1999a). Psychological therapies omitting a role for trauma-focused work may be more tolerable, potentially leading to better retention. However, there is evidence that the absence of a trauma-focus results in poorer outcomes (Bisson et al., 2013; Bradley et al., 2005; Jonas et al., 2013).

The issue of treatment tolerability and symptom exacerbation resulting from trauma-focused psychological therapies has been one of contention in the literature (Devilly & Foa, 2001; Hembree et al., 2003; Tarrier et al., 1999a). It is uncertain whether dropout rates vary as a function of treatment modality or whether those with a trauma-focus are associated with poorer retention. To date, a small number of meta-analyses have compared drop-out rates across different modalities of psychological therapy for PTSD (Bradley et al., 2005; Goetter et al., 2015; Hembree et al., 2003, Imel, Laska, Jakupcak, & Simpson, 2013). One of these studies reported no differences between therapies with and without exposure-work, however, the review is now dated and includes a far smaller number of studies than currently available (Hembree et al., 2003). Another review reported a trend towards greater dropout from exposure-based treatment, but did not analyse this statistically (Bradley et al., 2005). A more recent review reported that dropout was not associated with trauma-focus; however, studies comparing trauma-focused CBT to waitlist or usual care control groups were excluded, restricting the review to 42 studies (Imel et al., 2013). A more recent review found no difference in dropout rates from therapies that included exposure work in comparison to those that did not, but the review only included twenty studies of US military veterans (Goetter et al., 2015).

The aim of the current review was to ascertain rates of dropout across different modalities of psychological therapy and to determine whether some psychological therapies (especially those with a trauma-focus) were associated with higher rates of dropout than others. Since there is no agreed definition of dropout, we took the number of participants that had left the study at the point of post-treatment assessment as a proxy-indicator of dropout in order to allow the inclusion of data from a maximal number of studies. We also aimed to explore potential sources of heterogeneity among the included studies. Our overarching goal was to contribute to a refined understanding of dropout from psychological therapies for PTSD that will inform the development of treatment protocols that maximize retention.

2. Method

2.1. Selection criteria

Data on drop-out were extracted from studies that had been identified for a review of the efficacy of psychological therapies for adults with PTSD, which was undertaken as part of an update of the International Society for Traumatic Stress Studies (ISTSS) Treatment Guidelines (International Society of Traumatic Stress Studies (ISTSS), 2018). Both reviews had the same inclusion criteria. RCTs of any defined psychological therapy aimed at the reduction of PTSD-symptoms in comparison with a control group (e.g. usual care/waiting list); other psychological therapy; or psychosocial intervention (e.g. psychoeducation/relaxation training) were included. At least 70% of study participants were required to be diagnosed with PTSD with a duration of three months or more, according to DSM or ICD criteria determined by clinician diagnosis or an established diagnostic interview. This review considered studies of adults aged 18 or over, only. There were no restrictions based on symptom-severity or trauma-type. The diagnosis of PTSD was required to be primary and studies of comorbid PTSD and substance use disorder were excluded, but there were no other restrictions based on co-morbidity. Studies were only included if they reported data on the number of participants that had dropped out of the study by the point of post-treatment assessment. If multiple studies reported data on the same participants, dropout data were only included once. We also excluded RCTs of single-session interventions.

2.2. Search strategy

A search was conducted by the Cochrane Collaboration, which updated a previously published Cochrane review with the same inclusion criteria, which was published in 2013 (Bisson et al., 2013). The updated search aimed to identify all RCTs related to the prevention and treatment of PTSD, published from January 2008 to the 31 May 2018, using the search terms PTSD or posttrauma* or post-trauma* or ‘post trauma*’ or ‘combat disorder*’ or ‘stress disorder*’. The searches included results from PubMed, PsycINFO, Embase and the Cochrane database of randomized trials. This produced a group of papers related to the psychological treatment of PTSD in adults. We checked reference lists of the included studies. We searched the World Health Organization’s, and the US National Institutes of Health’s trials portals to identify additional unpublished or ongoing studies. We contacted experts in the field with the aim of identifying unpublished studies and studies that were in submission. A complementary search of the Published International Literature on Traumatic Stress (PILOTS) was also conducted.

2.3. Data extraction

Study characteristics and dropout data were extracted by two reviewers independently and in duplicate, using a form that had been pre-piloted. Since there is no agreed definition of dropout, taking the number of participants that had left the study at the point of post-treatment assessment allowed the inclusion of data from a maximal number of studies. Study authors were contacted to obtain missing data. Therapy classifications were agreed with the ISTSS treatment guidelines committee and posted on the ISTSS website to allow comment from the membership. Reasons for dropout and adverse events were not universally available or consistently reported by studies and it was not therefore possible to extract or meta-analyse these data.

2.4. Risk of bias assessment

All included studies were assessed for risk of bias at the study level, using Cochrane criteria (Higgins et al., 2011). This included: (1) sequence allocation for randomization (the methods used for randomly assigning participants to the treatment arms and the extent to which this was truly random); (2) allocation concealment (whether or not participants or personnel were able to foresee allocation to a specific group); (3) assessor blinding (whether the assessor was aware of group allocation); (4) incomplete outcome data (whether missing outcome data were handled appropriately); (5) selective outcome reporting (whether reported outcomes matched with those that were pre-specified); and (6) any other notable threats to validity (for example, premature termination of the study). Two researchers independently assessed each study and any conflicts were discussed with a third researcher with the aim of reaching a unanimous decision.

2.5. Data synthesis

Meta-analyses of proportion were conducted using the metaprop command in STATA version 13.1 (StataCorp, 2013). The metaprop command pools proportions and uses the score statistic and the exact binomial method to compute 95% confidence intervals (Thompson & Higgins, 2002). Data were pooled across all active psychological therapies. Sub-group analyses were also conducted to determine the dropout rate for each psychological therapy. A random effects model was chosen due to the heterogeneity across studies in terms of the inclusion and exclusion criteria of the studies; the populations from which the samples were drawn; the nature and duration of therapy; the predominant trauma type; and the mean age of participants.

Heterogeneity was assessed using both the I2 statistic (which indicates the proportion of the variance that is due to heterogeneity (Higgins & Green, 2011)) and visual inspection of the forest plots. To explore potential sources of heterogeneity, meta-regression was performed using the metareg function of STATA version 13.1 (StataCorp, 2013). Meta-regression assesses the association between study-level variables and the effect size (Thompson & Higgins, 2002). It was hypothesized that a number of study-level variables would result in higher rates of drop-out, these being: therapies having a trauma-focus (due to the possibility of these therapies being difficult for some participants to tolerate); therapies being delivered in a group-format (since drop out from group therapies has been found to be greater than from therapies delivered on an individual basis (Imel et al., 2013)); recruitment from clinical services rather than through advertisements (due to the likelihood of more severe symptoms and a possible tendency for these participants to be less motivated to engage in treatment); whether or not the participants were selected from military/veteran populations (due a greater likelihood of complex or severe PTSD); whether the trauma experienced by participants was sexual (due to the possibility of therapy being more difficult to tolerate); and the percentage of participants who were University educated (due to the possibility that more educated participants are better able to grasp the concepts involved in therapy). To explore the possibility of publication bias, we constructed a funnel plot using data on dropout from all active therapy groups.

3. Results

The original Cochrane review included 70 RCTs. The update search identified 5500 potentially eligible studies published since 2008. Abstracts were reviewed and full-text copies obtained for 203 potentially relevant studies. Forty-four new RCTs met inclusion criteria for the review and reported data on dropout at the point of post-treatment assessment. This resulted in a total of 115 RCTs of 7724 participants. Figure 1 presents a flow diagram for study selection.

Figure 1.

Figure 1.

Open in a new tab

Study flow diagram.

3.1. Study characteristics

Study characteristics are summarized in Table 1. Twenty-eight defined psychological therapies were evaluated. Eight of these were broadly categorized as CBT with a Trauma Focus (CBT-T) delivered on an individual basis: Brief Eclectic Psychotherapy (BEP); Cognitive Processing Therapy (CPT); Cognitive Therapy (CT); Narrative Exposure Therapy (NET); Prolonged Exposure (PE); Reconsolidation of Traumatic Memories (RTM); Virtual Reality Exposure Therapy (VRE) and CBT-T (not based on a specific model). Thirteen other therapies delivered to individuals were evaluated: EMDR; CBT without a Trauma Focus; Present Centred Therapy (PCT); Supportive Counselling; Written Exposure Therapy; Observed and Experiential Integration (OEI); Interpersonal Psychotherapy; Psychodynamic Psychotherapy; REM Desensitization; Emotional Freedom Technique (EFT); Dialogical Exposure Therapy (DET); Internet-based CBT; and Relaxation Training. There were six different types of group therapy: Group CBT-T; Group Present Centred Therapy (PCT); Group and Individual CBT-T; Group Stabilizing Treatment; Group Interpersonal Therapy; Group Supportive Counselling. There were also RCTs of couples CBT-T. There were six types of control group: psychoeducation; couples psychoeducation; internet-based psychoeducation; waitlist; treatment as usual; and minimal attention/symptom monitoring.

Table 1.

Characteristics of included studies.

Study N Country Intervention 1 Intervention 2 Intervention 3 Intervention 4 Population Trauma type % Female % Unemployed % University Educated
Acarturk et al. (2016) 98 Turkey/Syria EMDR WL     Refugees War/Persecution 74 Unknown 4
Adenauer et al. (2011) 34 Germany NET (CBT-T) WL     Refugees War/Persecution 44 Unknown Unknown
Ahmadi, Hazrati, Ahmadizadeh and Noohi (2015) 48 Iran EMDR REM Desensitization WL   Military Personnel/Veterans Military Trauma 0 Unknown 33.3
Akbarian et al. (2015) 40 Iran Group CBT-T MC/RA     General Population Various 79 Unknown Unknown
Asukai, Saito, Tsuruta, Kishimoto and Nishikawa (2010) 24 Japan PE (CBT-T) TAU     General Population Various 88 Unknown Unknown
Beck, Coffey, Foy, Keane, & Blanchard (2009) 44 USA Group CBT-T MC/RA     General Population Road Traffic Accident 82 54 Unknown
Bichescu, Neuner, Schauer and Elbert (2007) 18 Romania NET (CBT-T) Psychoeducation     General Population Political detainment 94 0 72
Blanchard et al. (2003) 98 USA CBT-T SC WL   General Population Road Traffic Accident 73 Unknown Unknown
Bradshaw, McDonald, Grace, Detwiler and Austin (2014) 10 Canada OEI WL     General Population Various 70 0 Unknown
Brom, Kleber and Defares (1989) 83 Netherlands CBT-T Psychodynamic Therapy WL   General Population Various 79 49 Unknown
Bryant, Moulds, Guthrie, Dang and Nixon (2003) 58 Australia CBT-T SC     General Population Various 52 Unknown Unknown
(Bryant et al., 2011) 28 Thailand CBT-T SC     General Population Terrorism 96 84% Unknown
(Buhmann, Nordentoft, Ekstroem, Carlsson, & Mortensen, 2016) 138 Denmark CBT-T WL     Refugees Organized Violence 41 Unknown Unknown
(Butollo, Karl, König, & Rosner, 2016) 148 Germany CPT (CBT-T) DET     General Population Various 66 Unknown Unknown
(Capezzani et al., 2013) 21 Italy EMDR CBT-T     General Population Medical Diagnoses/Emergencies 90 Unknown Unknown
(Carletto et al., 2016) 50 Italy EMDR Relaxation Training     General Population Medical Diagnoses/Emergencies 81 Unknown Unknown
(Carlson, Chemtob, Rusnak, Hedlund, & Muraoka, 1998) 35 USA EMDR Relaxation Training TAU   Military Personnel/Veterans Military Trauma 0 62 Unknown
(Castillo et al., 2016) 86 USA Group CBT-T WL     Military Personnel/Veterans Military Trauma 100 44 Unknown
(Chard, 2005) 71 USA CPT (CBT-T) WL     General Population Sexual Assault or Rape 100 Unknown Unknown
(Cloitre, Koenen, Cohen, & Han, 2002b) 58 USA CBT-T WL     General Population Child Abuse 100 24 52
(Cloitre et al., 2010) 71 USA CBT-T CBT without a trauma focus     General Population Child Abuse 100 31 Unknown
Cooper (1989) 16 USA EMDR Relaxation Therapy     Military Personnel/Veterans Military Trauma 0 Unknown Unknown
(Devilly, Spence, & Rapee, 1998) 35 Australia EMDR TAU     Military Personnel/Veterans Military Trauma 0 Unknown Unknown
(Devilly & Spence, 1999) 32 Australia EMDR CBT-T     General Population Various 100 Unknown Unknown
(Dorrepaal et al., 2012) 71 Netherlands Group Stabilizing Treatment TAU     General Population Child Abuse Unknown 83 Unknown
(Duffy, Gillespie, & Clark, 2007) 58 UK CT (CBT-T) WL     General Population Various 40 Unknown Unknown
(Dunne, Kenardy, & Sterling, 2012) 26 Australia CBT-T WL     General Population Road Traffic Accident 50 31 73
(Echeburua, Zubizarreta, & Sarasua, 1997) 20 Spain CBT-T Relaxation Training     General Population Sexual Assault or Rape 100 Unknown 20
(Ehlers, Clark, Hackmann, McManus, & Fennell, 2005) 28 UK CT (CBT-T) WL     General Population Various 50 25 35
(Ehlers et al., 2003) 57 UK CT (CBT-T) MC/RA     General Population Road Traffic Accident Unknown Unknown Unknown
(Ehlers et al., 2014) 91 UK CT (CBT-T) SC WL   General Population Various 58 23 26
(Falsetti, Resnick, & Davis, 2008) 60 USA Group CBT-T WL     General Population Various 100 Unknown Unknown
(Fecteau & Nicki, 1999) 20 Canada CBT-T WL     General Population Road Traffic Accident 70 Unknown Unknown
(Feske, 2008) 21 USA PE (CBT-T) TAU     General Population Various 100 29% 90%
(Foa, Rothbaum, Riggs, & Murdock, 1991) 45 USA PE (CBT-T) CBT without a trauma focus Supportive counselling WL General Population Sexual Assault or Rape 100 Unknown Unknown
(Foa et al., 1999) 66 USA PE (CBT-T) CBT without a trauma focus WL   General Population Sexual Assault or Rape 100 38 41
(Foa et al., 2005) 179 USA PE (CBT-T) WL     General Population Assault 100 17 34
(Foa et al., 2018) 256 USA Spaced PE (CBT-T) PCT MC/RA   Military Personnel/Veterans Military Trauma 12 100 66
(Fonzo et al., 2017) 66 USA PE (CBT-T) WL     General Population Various 65 Unknown Unknown
(Forbes et al., 2012) 59 Australia CPT (CBT-T) TAU     Military Personnel/Veterans Military Trauma 4 36 Unknown
(Ford, Steinberg, & Zhang, 2011) 146 USA CBT without a trauma focus PCT WL   General Population Various 100 Unknown 22
(Ford, Chang, Levine, & Zhang, 2013) 80 USA Group CBT-T Group Supportive Counselling     Incarcerated Women Various 100 Unknown Unknown
(Galovski, Blain, Mott, Elwood, & Houle, 2012) 100 USA CPT (CBT-T) MC/RA     General Population Various 69 Unknown Unknown
(Gamito et al., 2010) 10 Portugal VRE (CBT-T) Control Exposure WL   Military Personnel/Veterans Military Trauma 0 Unknown Unknown
(Gersons, Carlier, Lamberts, & Van der Kolk, 2000) 42 Netherlands BEP (CBT-T) WL     General Population Various Unknown Unknown Unknown
(Gray, Budden-Potts, & Bourke, 2017) 74 USA RTM (CBT-T) WL     Military Personnel/Veterans Military Trauma 0 Unknown Unknown
(Hensel-Dittmann et al., 2011) 28 Germany NET (CBT-T) CBT without a trauma focus     Asylum Seekers Organized Violence Unknown Unknown Unknown
(Hinton et al., 2005) 40 USA CBT-T WL     Refugees Genocide 60 Unknown Unknown
(Hinton, Hofmann, Rivera, Otto, & Pollack, 2011) 24 USA Group CBT-T WL     General Population Various 100 Unknown Unknown
(Hogberg et al., 2007) 24 Sweden EMDR WL     General Population Various 38 Unknown Unknown
(Hollifield, Sinclair-Lian, Warner, & Hammerschlag, 2007) 55 USA Group trauma-focused CBT WL     General Population Various 68 Unknown 40
(Ironson, Freund, Strauss, & Williams, 2002) 22 USA EMDR PE (CBT-T)     General Population Various 77 Unknown Unknown
(Ivarsson et al., 2014) 62 Sweden I-CBT WL     General Population Various 82 8 65
(Jacob, Neuner, Maedl, Schaal, & Elbert, 2014) 76 Rwanda NET (CBT-T) WL     Genocide Survivors Genocide 92 Unknown Unknown
(Jensen, 1994) 25 USA EMDR WL     Military Personnel/Veterans Military Trauma 0 68 Unknown
(Johnson, Zlotnick, & Perez, 2011) 70 USA CBT without a trauma focus TAU     General Population Domestic Abuse 100 73 7
(Johnson, Johnson, Perez, Palmieri, & Zlotnick, 2016) 60 USA CBT without a trauma focus TAU     General Population Domestic Abuse 100 77 5
(Karatzias et al., 2011) 46 UK EMDR EFT     General Population Various 57 37 47
(Keane, Fairbank, Caddell, & Zimering, 1989) 24 USA CBT-T WL     Military Personnel/Veterans Military Trauma 0 Unknown Unknown
(Krupnick et al., 2008) 48 USA Group IPT WL     General Population Various 100 80 13%
(Kubany, Hill, & Owens, 2003) 37 USA CBT-T WL     General Population Domestic Abuse 100 Unknown Unknown
(Kubany, Hill, & Owens, 2004) 107 USA CBT-T WL     General Population Domestic Abuse 100 Unknown Unknown
(Laugharne et al., 2016) 20 Australia EMDR PE (CBT-T)     General Population Various 70 Unknown Unknown
(Lee, Gavriel, Drummond, Richards, & Greenwald, 2002) 24 Australia CBT-T EMDR     General Population Various 46 Unknown Unknown
(Lewis et al., 2017) 42 UK I-CBT WL     General Population Various 57 19 62
Lindauer 24 Netherlands BEP WL     General Population Various 54 Unknown Unknown
Littleton (2016) (Littleton, Grills, Kline, Schoemann, & Dodd, 2016) 87 USA I-CBT I-Psychoeducation     General Population Sexual Assault or Rape 100 Unknown Unknown
(Litz, Engel, Bryant, & Papa, 2007) 45 USA I-CBT I-SC     Military Personnel/Veterans Terrorism/Military Trauma Unknown Unknown Unknown
(Marcus, Marquis, & Sakai, 1997) 67 USA EMDR TAU     General Population Various 79 Unknown Unknown
(Markowitz et al., 2015) 110 USA IPT PE (CBT-T) Relaxation Therapy   General Population Various 70 21 Unknown
(Marks, Lovell, Noshirvani, Livanou, & Thrasher, 1998) 87 UK PE (CBT-T) Cognitive Restructuring PE (CBT-T) (CBT-T)(CBT-T)and Cognitive Restructuring Relaxation without PE (CBT-T) (CBT-T)(CBT-T)or CR General Population Various 36 54 Unknown
(McDonagh et al., 2005) 74 USA PE (CBT-T) PCT WL   General Population Sexual Assault or Rape 100 17 Unknown
(McLay et al., 2011) 20 USA VRE (CBT-T) TAU     Military Personnel/Veterans Military Trauma 5 Unknown Unknown
(McLay et al., 2017) 81 USA VRE (CBT-T) Control Exposure Therapy     Military Personnel/Veterans Military Trauma 4 Unclear Unclear
(Monson et al., 2012) 20 USA Couples CBT-T WL     General Population Various 25 40 Unknown
(Monson et al., 2006) 60 USA CPT (CBT-T) WL     Military Personnel/Veterans Military Trauma 10 Unknown Unknown
(Morath et al., 2014) 38 Germany NET (CBT-T) WL     Refugees Organized Violoence 32 Unknown Unknown
(Mueser et al., 2008) 108 USA CBT-T TAU     General Population Various 79 Unknown Unknown
(Nacasch et al., 2011) 30 Israel PE (CBT-T) TAU     Military Personnel/Veterans Military Trauma Unknown 63 Unknown
(Neuner et al., 2010) 32 Germany NET (CBT-T) TAU     Refugees Torture 31 Unknown Unknown
(Neuner et al., 2008) 277 Uganda NET (CBT-T) SC Monitoring   Refugees War/Persecution 51 49 Unknown
(Neuner, Schauer, Klaschik, Karunakara, & Elbert, 2004) 43 Uganda NET (CBT-T) SC Psychoeducation   Refugees War/Persecution 60 28 Unknown
(Nijdam, Gersons, Reitsma, de Jongh, & Olff, 2012) 140 Netherlands BEP (CBT-T) EMDR     General Population Various 56 Unknown 30
(Pacella et al., 2012) 66 USA PE (CBT-T) (CBT-T) MC/RA     General Population Medical Diagnoses/Emergencies 37 Unknown Unknown
(Paunovic, 2011) 29 Sweden CBT-T WL     General Population Various 63 74 11
(Peniston & Kulkosky, 1991) 29 USA CBT-T TAU     Military Personnel/Veterans Military Trauma Unknown Unknown Unknown
(Power et al., 2002) 105 UK EMDR CBT-T WL   General Population Various 42 Unknown Unknown
(Rauch et al., 2015) 36 USA PE (CBT-T) (CBT-T) PCT     Military Personnel/Veterans Military Trauma 9 Unknown Unknown
(Ready, Gerardi, Backscheider, Mascaro, & Rothbaum, 2010) 11 USA VRE (CBT-T) PCT     Military Personnel/Veterans Military Trauma Unknown Unknown Unknown
(Reger et al., 2016) 162 USA VRE (CBT-T) PE (CBT-T) WL   Military Personnel/Veterans Military Trauma 4 Active duty 7
(Resick et al., 2015) 108 USA Group CBT-T Group PCT     Military Personnel/Veterans Military Trauma 8 0 8
(Resick et al., 2002) 171 USA CPT (CBT-T) (CBT-T) PE (CBT-T) Minimal Attention   General Population Sexual Assault or Rape 100 Unknown Unknown
(Resick et al., 2017) 268 USA CPT (CBT-T) (CBT-T) Group CBT-T     Military Personnel/Veterans Military Trauma 9 100 19
(Rothbaum, 1997) 18 USA EMDR WL     General Population Sexual Assault or Rape 100 19 43
(Rothbaum, Astin, & Marsteller, 2005) 60 USA PE (CBT-T) EMDR WL   General Population Sexual Assault or Rape 100 Unknown Unknown
(Sautter, Glynn, Cretu, Senturk, & Vaught, 2015) 57 USA Couples CBT without a trauma focus Couples Psychoeducation     Military Personnel/Veterans Military Trauma 1.75 12 75
(Scheck, Schaeffer, & Gillette, 1998) 60 USA EMDR SC     General Population Various 100 Unknown Unknown
(Schnurr et al., 2003) 360 USA Group CBT-T Group PCT     Military Personnel/Veterans Military Trauma 0 51 Unknown
(Schnurr et al., 2007) 284 USA PE (CBT-T) (CBT-T) Group PCT     Military Personnel/Veterans Military Trauma 100 38 Unknown
(Schnyder, Müller, Maercker, & Wittmann, 2011) 30 Switzerland BEP (CBT-T) MC/RA     General Population Various 46.7 Unknown Unknown
Shemesh 60 USA CBT-T Psychoeducation     General Population Medical Diagnoses/Emergencies 33 Unknown Unknown
(Sloan, Marx, Bovin, Feinstein, & Gallagher, 2012) 46 USA WET WL     General Population Road Traffic Accident Unclear 78 41
(Sloan, Marx, Lee, & Resick, 2018) 126 USA WET CPT (CBT-T)     General Population Various 49 Unknown 13
(Spence et al., 2011) 42 Australia I-CBT WL     General Population Various 81 41 Not clear
(Stenmark, Catani, Neuner, Elbert, & Holen, 2013) 81 Norway NET (CBT-T) TAU     Refugees Various 31 Unknown 25
(Suris, Link-Malcolm, Chard, Ahn, & North, 2013) 86 USA CPT (CBT-T) PCT     Military Personnel/Veterans Sexual Assault or Rape 85 43 16
(Taylor et al., 2003) 60 USA PE (CBT-T) Relaxation Therapy EMDR   General Population Various 75 13 Unknown
(Tylee, Gray, Glatt, & Bourke, 2017) 30 USA RTM (CBT-T) WL     General Population Military Trauma 0 Unknown Unknown
(Vaughan et al., 1994) 36 Australia CBT-T Relaxation Training EMDR   General Population Various 64 Unknown Unknown
(Wells et al., 2015) 32 UK PE (CBT-T) CBT without a trauma focus WL   General Population Various 38 6 Unknown
(Wells & Sembi, 2012) 20 UK CBT without a trauma focus WL     General Population Various 55 Unknown Unknown
(Yehuda et al., 2014) 52 USA PE (CBT-T) MC/RA     Military Personnel/Veterans Military Trauma Unclear Unknown Unknown
(Zang, Hunt, & Cox, 2014) 20 China NET (CBT-T) WL     General Population Earthquake 90 Unknown Unknown
(Zang, Hunt, & Cox, 2013) 22 China NET (CBT-T) WL     General Population Earthquake 77 Unknown Unknown
(Zlotnick et al., 1997) 48 USA Group CBT-T WL     General Population Sexual Assault or Rape 100 Unknown 33
Open in a new tab

BEP =Brief Eclectic Psychotherapy; NET = Narrative Exposure Therapy

CBT =Cognitive Behavioural Therapy; OEI =Observed and Experimental Integration

CBT-T =Cognitive Behavioural Therapy with a Trauma focus; PCT =Present Centred Therapy

CPT =Cognitive Processing Therapy; PE =Prolonged Exposure

CR =Cognitive Restructuring; REM Desensitization =Rapid Eye Movement Desensitization

CT =Cognitive Therapy; RTM =Reconsolidation of Traumatic Memories

DET =Dialogical Exposure Therapy; SC =Supportive Counselling

EFT =Emotional Freedom Technique; TAU =Treatment as Usual

EMDR = Eye Movement Desensitization and ReprocessingVRE =Virtual Reality Exposure

I-CBT = Internet-based Cognitive Behavioural Therapy; WET = Written Emotion Therapy

I-Psychoeducation =Internet-based Psychoeducation; WL =Waiting List

IPT =Interpersonal Psychotherapy

I-SC =Internet-based Supportive Counselling

MC/RA =Medical Checks/Repeated Assessments

The number of randomized participants ranged from 10 to 360. Studies were conducted in Australia (9), Canada (2), China (2), Denmark (1), Germany (5), Iran (2), Israel (1), Italy (2), Japan (1), the Netherlands (5), Norway (1), Portugal (1), Romania (1), Rwanda (1), Spain (1), Sweden (3), Switzerland (1), Thailand (1), Turkey/Syria (1), Uganda (2), UK (10) and USA (62). Participants were traumatized by military trauma (27 studies), sexual assault or rape (11 studies), war/persecution (4 studies), road traffic accidents (6 studies), earthquakes (2 studies), childhood abuse (3 studies), political detainment (1 study), terrorism (2 studies), physical assault (2 studies), domestic abuse (4 studies), medical diagnoses/emergencies (4 studies), genocide (1 study) and organized violence (3 studies). The remainder included individuals traumatized by various different traumatic events. There were 27 studies of females only and 10 of only males; the percentage of females in the remaining studies ranged from 1.75% to 96%. The percentage with a University education ranged from 4% to 90%.

3.2. Risk of bias

Risk of bias assessments for the included studies are summarized in Table 2. Fifty-two studies reported a method of sequence allocation judged to pose a ‘low’ risk of bias; five reported a method with a ‘high’ risk of bias; the remainder reported insufficient details and were, therefore, rated as ‘unclear’. Forty-one studies reported methods of allocation concealment representing a ‘low’ risk of bias; two a method with a ‘high’ risk of bias; with the remainder rated as ‘unclear’. The outcome assessor was aware of the participant’s allocation in 11 of the included studies; it was unclear whether the outcome assessor was aware of group allocation in 20 studies; with the remainder using blind-raters or self-report questionnaires delivered in a way that could not be influenced by members of the research team. Twenty-three studies were judged as posing a ‘high’ risk of bias in terms of incomplete outcome data; 79 studies were felt to have dealt with dropouts appropriately (‘low’ risk of bias); it was unclear in the remaining studies. The majority of studies failed to reference a published protocol, resulting in an ‘unclear’ risk of selective reporting for 75 studies; risk of bias was judged as ‘high’ in five studies and low in the remainder. Seventy of the included studies presented a ‘high’ risk of bias in other areas, for example, in relation to sample size, baseline imbalances between groups, or other methodological shortfalls. We could not rule out potential researcher allegiance, since treatment originators were involved in the evaluation of their own intervention in many of the included studies.

Table 2.

Risk of bias assessments of the included studies.

  Random sequence generation Allocation concealment Incomplete outcome data assessment Blinding of outcome Selective reporting Other sources of bias Total no. high risk
(Acarturk et al., 2016) Low Low Low Low Low Low 0
(Adenauer et al., 2011) Low Low Low Low High High 2
(Ahmadi et al., 2015) Unclear Unclear High Unclear Unclear High 2
(Akbarian et al., 2015) Low High Low Low Unclear High 2
(Asukai et al., 2010) Low Low Low Low Unclear High 1
(Beck et al., 2009) Unclear Unclear High Low Unclear High 2
(Bichescu et al., 2007) High Unclear Low Low Unclear High 2
(Blanchard et al., 2003) High Unclear Low Low Unclear Low 1
(Bradshaw et al., 2014) Unclear Unclear Low High Unclear High 2
(Brom et al., 1989) Unclear Unclear High Unclear Unclear High 2
(Bryant et al., 2003) Low Unclear Low Low Low High 1
(Bryant et al., 2011) Low Low Low Low Unclear High 1
(Buhmann et al., 2016) Low Low Unclear Low Low Low 0
(Butollo et al., 2016) Unclear Unclear Low Low Unclear High 1
(Capezzani et al., 2013) Unclear Unclear Low Low Unclear High 1
(Carletto et al., 2016) Low Low High Low Low Low 1
(Carlson et al., 1998) Unclear Unclear High Unclear Unclear Low 1
(Castillo et al., 2016) Unclear Unclear Low Low Unclear High 1
(Chard, 2005) Unclear Unclear Low Low Unclear High 1
(Cloitre et al., 2002b) Unclear Unclear Low Low High Low 1
(Cloitre et al., 2010) Unclear Low Low Low Low Low 0
(Cooper & Conklin, 2015) High High High Unclear Low High 4
(Devilly et al., 1998) Unclear Unclear High Low Unclear Low 1
(Devilly & Spence, 1999) High Unclear High Unclear Unclear High 3
(Dorrepaal et al., 2012) Unclear Low Low Low High High 2
(Duffy et al., 2007) Low Low Low Unclear Low High 1
(Dunne et al., 2012) Unclear Unclear Low Unclear Unclear High 1
(Echeburua et al., 1997) Unclear Unclear Low Unclear Unclear High 1
(Ehlers et al., 2003) Low Low High Low Unclear High 2
(Ehlers et al., 2005) Unclear Unclear Low Low Unclear High 2
(Ehlers et al., 2014) Unclear Low Low Low Low Low 0
(Falsetti et al., 2008) Unclear Unclear Low Low High High 2
(Fecteau & Nicki, 1999) Low Unclear High Unclear Unclear High 2
(Feske, 2008) Unclear Unclear Low Unclear Unclear High 1
(Foa et al., 1991) Unclear Unclear High Low Unclear High 2
(Foa et al., 1999) Unclear Unclear Low Low Unclear High 1
(Foa et al., 2005) Low Low Low Low Unclear Low 0
(Foa et al., 2018) Low Low Low Low Low Low 0
(Fonzo et al., 2017) Low Unclear Low Unclear Low Low 0
(Forbes et al., 2012) Unclear Low Low Unclear Unclear High 1
(Ford et al., 2011) Low Low Low Low Unclear High 1
(Ford et al., 2013) Low Low High Low Unclear High 2
(Galovski et al., 2012) Unclear Unclear Low Low Unclear Low 0
(Gamito et al., 2010) Unclear Unclear Unclear Unclear High High 2
(Gersons et al., 2000) Unclear Unclear Low Low Unclear Low 0
(Gray et al., 2017) Low Low Unclear Unclear Unclear Unclear 0
(Hensel-Dittmann et al., 2011) Low Low Low Low Unclear Low 0
(Hinton et al., 2005) Low Unclear Low Low Unclear High 1
(Hinton et al., 2011) Unclear Unclear Low Unclear Unclear High 1
(Hogberg et al., 2007) Low Unclear High Low Unclear High 2
(Hollifield et al., 2007) Low Low Low Low Unclear High 1
(Ironson et al., 2002) Unclear Unclear Low High Unclear High 2
(Ivarsson et al., 2014) Low Unclear Low Low Low High 1
(Jacob et al., 2014) Low Low Low Low Unclear High 1
(Jensen, 1994) Unclear Unclear High Unclear Unclear High 2
(Johnson et al., 2011) Low Unclear Low High Unclear Low 1
(Johnson et al., 2016) Low Low Low Low Unclear Low 0
(Karatzias et al., 2011) Low Low Low Low Unclear High 1
(Keane et al., 1989) Unclear Unclear Unclear High Unclear High 2
(Krupnick et al., 2008) Unclear Unclear Low Unclear Unclear High 1
(Kubany et al., 2003) Unclear Unclear Low Low Unclear High 1
(Kubany et al., 2004) Unclear Unclear Low Low Low High 1
(Laugharne et al., 2016) Low Low Low Low Unclear High 1
(Lee et al., 2002) Unclear Unclear Low Low Unclear High 1
(Lewis et al., 2017) Low Low Low Low Low High 1
(Lindauer et al., 2005) Low Low Low Low Low High  
(Littleton et al., 2016) Low Unclear Low High Low Low 1
(Litz et al., 2007) Unclear Unclear High Low Low High 2
(Marcus et al., 1997) Unclear Unclear Unclear High Unclear High 2
(Markowitz et al., 2015) Low Low Low Low Low High 1
(Marks et al., 1998) Unclear Unclear Low Low Unclear Low 0
(McDonagh et al., 2005) Unclear Unclear Low Low Unclear Low 0
(McLay et al., 2011) Low Low Unclear High Unclear High 2
(McLay et al., 2017) Low Unclear Low Low Low Low 0
(Monson et al., 2012) Low Low Low Low Low Low 0
(Monson et al., 2006) Low Low Low Low Unclear Low 0
(Morath et al., 2014) Low Low Unclear Low Low Low 0
(Mueser et al., 2008) Low Low Low Low Unclear High 1
(Nacasch et al., 2011) Low Unclear Low Low Low High 1
(Neuner et al., 2004) Low Unclear Low Low Low High 1
(Neuner et al., 2008) Unclear Unclear Low Low Unclear Low 0
(Neuner et al., 2010) Unclear Unclear Low Low Unclear High 1
(Nijdam et al., 2012) Unclear Low Low Low Low Low 0
(Pacella et al., 2012) Low Unclear Low Low Unclear Low 0
(Paunovic, 2011) Unclear Unclear Low High Unclear High 2
(Power et al., 2002) Low Low High Low Unclear Low 1
(Rauch et al., 2015) Unclear Unclear Low Low Unclear High 1
(Ready et al., 2010) Unclear Unclear Unclear Low Unclear High 1
(Reger et al., 2016) Low Low Low Low Unclear Low 0
(Resick et al., 2002) Unclear Unclear Low Low Unclear High 1
(Resick et al., 2015) Unclear Unclear Low Low Unclear Low 0
(Resick et al., 2017) Low Unclear Low Low Low Low 0
(Rothbaum, 1997) Unclear Unclear High Low Unclear High 2
(Rothbaum et al., 2005) Unclear Unclear High Low Unclear Low 1
(Sautter et al., 2015) Unclear Unclear Low Low Unclear Low 0
(Scheck et al., 1998) Low Low High Unclear Unclear High 2
(Schnurr et al., 2003) High Unclear Low Low Low Low 1
(Schnurr et al., 2007) Low Low Low Low Low Low 0
Shemesh Low Low Unclear Unclear Unclear Low 0
(Sloan et al., 2012) Low Low Unclear Low Unclear Low 0
(Sloan et al., 2018) Low Low Low Low Low Low 0
(Spence et al., 2011) Low Unclear High High Low Unclear 2
(Stenmark et al., 2013) Unclear Unclear Low High Low High 2
(Suris et al., 2013) Unclear Unclear Low Low Low High 1
(Taylor et al., 2003) Unclear Unclear Low Low Unclear Low 0
(Tylee et al., 2017) Unclear Unclear Unclear Low Unclear High 1
(Vaughan et al., 1994) Unclear Unclear Low Low Unclear Low 0
(Wells & Sembi, 2012) Low Low Low Low Unclear High 1
(Wells et al., 2015) Low Low High High Unclear High 3
(Yehuda et al., 2014) Unclear Unclear High Unclear Unclear Unclear 1
(Zang et al., 2013) Unclear Unclear Low Low Low High 1
(Zang et al., 2014) Low Unclear Low Low Low High 1
(Zlotnick et al., 1997) Unclear Unclear High Low Low High 2
Open in a new tab

3.3. Dropout

Across the different modalities of psychological therapy, dropout rates from individual studies ranged from 0%-65%. The pooled dropout rate from psychological therapies for PTSD was 16% (95% CI 14–18; k = 116) with substantial heterogeneity across studies (I2 = 77.3%). The dropout rate for each modality of psychological therapy is presented in Table 3. The heterogeneity in dropout rates indicates differences that may be predicted by the variables entered into meta-regression.

Table 3.

Results of the meta-analyses of dropout.

  Number of studies Mean % drop out (95% CI) I2 (%)
1. CBT-T (not based on a specific model) 25 13 (9–18) 64.41
2. Brief Eclectic Psychotherapy 3 17 (0–51) 90.40
3. Cognitive Processing Therapy (CPT) 8 30 (22–39) 75.15
4. Cognitive Therapy (CT) 6 9 (1–23) 82.72
5. Narrative Exposure Therapy 11 12 (3–26) 85.59
6. Prolonged Exposure (PE) 22 22 (16–28) 72.56
7. Reconsolidation of Traumatic Memories (RTM) 1 1 (0–8) 0.00
8. Virtual Reality Exposure (VRE) 5 18 (3–38) 76.32
9. Eye Movement Desensitization and Reprocessing (EMDR) 21 18 (12–24) 62.13
10. CBT without a trauma focus 9 14 (7–23) 61.96
11. Present Centred Therapy (PCT) 6 20 (13–28) 40.85
12. Supportive Counselling 9 15 (3–32) 87.84
13. Observed and Experiential Integration (OEI) 1 0 Not applicable
14. Interpersonal Psychotherapy (IPT) 1 15 (6–30) Not applicable
15. Psychodynamic Psychotherapy 1 14 Not applicable
16. REM Desensitization 1 38 Not applicable
17. Emotional Freedom Technique (EFT) 1 39 Not applicable
18. Dialogical Exposure Therapy (DET) 1 12 Not applicable
19. Internet-based CBT 3 16 (8–26) 32.12
20. Relaxation Training 8 10 (3–19) 56.80
21. Group CBT with a Trauma Focus (group CBT-T) 9 24 (16–33) 76.29
22. Group Present Centred Therapy (PCT) 3 14 (11–18) 0.00
23. Group and Individual CBT-T 1 22 Not applicable
24. Group Stabilizing Treatment 1 18 Not applicable
25. Group Interpersonal Psychotherapy 1 38 Not applicable
26. Group Supportive Counselling 1 3 Not applicable
27. Couples CBT-T 2 22 (11–36) 0.00
28. Psychoeducation 3 1 (0–7) 0.00
29. Couples Psychoeducation 3 12 (3–25) 64.00
30. Internet-based psychoeducation 1 7 Not applicable
31. Waitlist 53 11 (8–15) 65.43
32. Treatment usual 14 13 (7–19) 61.37
33. Minimal attention/symptom monitoring 8 13 (2–32) 92.30
Open in a new tab

3.4. Meta-regression

Results of the meta-regressions are presented in Table 4. We found evidence that psychological therapies with a trauma-focus were significantly associated with greater dropout (β = 0.069; CI 0.011–0.127; P = 0.021; dropout rate of 18% (95% CI 15–21%) from those with a trauma focus versus 14% (95% CI 10–18%) from those without a trauma focus). There was no evidence of greater dropout from therapies delivered in a group format; from studies that recruited participants from clinical services rather than via advertisements; that included only military personnel/veterans; that included only participants traumatized by sexual traumas; from studies with a higher proportion of female participants; or from studies with a lower proportion of participants who were University educated.

Table 4.

Meta-regression of study-level variables on dropout from all active psychological therapies.

Variable β (95% confidence intervals) P
Trauma focus 0.069 (0.011–0.127) 0.021
Recruitment from clinical services −0.028 (−0.087–0.030) 0.341
Delivered in a group format −0.022 (−0.096–0.523) 0.564
Sample drawn from military population 0.032 (−0.023–0.087) 0.251
Sexual trauma 0.040 (−0.049–0.130) 0.376
% Female 0.040 (−0.049–0.130) 0.376
% University educated 0.001 (−0.003–0.001) 0.208
Open in a new tab

Trauma-focus coded as 0 = non-trauma focused, 1 = trauma focused; recruitment method coded as 0 = not recruited from clinical services, 1 = recruited from clinical services; delivered in a group format coded as 0 = not delivered in a group format, 1 = not delivered in a group format; sample drawn from military population coded 0 = not from a military population; 1 = from a military population; sexual trauma coded 0 = not a sexual trauma; 1 = a sexual trauma.

3.5. Publication bias

A funnel plot (see Figure 2), which was constructed using data on dropout from all active therapy groups, did not show evidence of publication bias.

Figure 2.

Figure 2.

Open in a new tab

Funnel plot.

4. Discussion

4.1. Main findings

Taking the number of participants that had left the study at the point of post-treatment assessment as a proxy-indicator of dropout, the pooled rate from psychological therapies for PTSD was 16% (95% CI 14–18%). This is of a similar magnitude to a previous meta-analysis of 42 studies, which found an average dropout rate of 18% (Imel et al., 2013) using the definition of dropout given by the included studies. This is also similar to the dropout rate of 17.5% obtained from a meta-analysis of dropout from RCTs of psychotherapy for depression (Cooper & Conklin, 2015) that defined dropout as unexpected attrition among individuals who were randomized to a treatment but failed to complete it. It was considerably lower than the pooled drop-out rate of 36% found by a more recent review of twenty studies of US military veterans (Goetter et al., 2015). This was in comparison to a pooled dropout rate from studies of veterans/military personnel in this review of 18% (95% CI 15–22%). This is likely to reflect the fact that the previous review included a variety of different study designs including naturalistic studies and used the definition of dropout given by the authors of individual studies.

There was no evidence of greater dropout from therapies delivered in a group format. This contradicts the findings of earlier reviews that found group delivery to be associated with a significant increase in dropout (Goetter et al., 2015; Imel et al., 2013). This may be the result of more recent studies evaluating interventions that have been optimized to increase retention or more proactive attempts to retain participants. There was also no evidence of significantly greater dropout from studies that recruited participants from clinical services rather than via advertisements; that included only military personnel/veterans; that included only participants traumatized by sexual traumas; that included only female participants; and from studies with a lower proportion of participants who were University educated. Research looking at factors associated with dropout have yielded inconsistent findings (Bryant et al., 2007; Schottenbauer et al., 2008; Taylor, 2003). Although the findings of the current review contradict some previous studies; they are in agreement with others. Inconsistencies may be the result of difference in study type and design; the types of interventions of interest and the degree to which they are protocolized; or may vary according to the populations of interest.

We found evidence that psychological therapies with a trauma-focus were significantly associated with greater dropout. This challenges the findings of previous, far smaller, meta-analyses, which found no significant differences in dropout rates from therapies with and without a trauma-focus (Goetter et al., 2015; Hembree et al., 2003). However, one of these studies found a significant difference between PCT (a non-trauma-focused intervention) and a group of therapies that had a trauma-focus (Imel et al., 2013). Our findings may be a result of the accumulated data available from a larger number of studies. The results, however, are consistent with the findings of a review of seven studies of treatments specifically targeting child abuse-related or complex PTSD, which found some evidence of greater drop-out from exposure-based therapies (Dorrepaal et al., 2014). Although there are many reasons for dropout from psychological therapies, this finding suggests that difficulties tolerating trauma-focused treatment may be one of these. Adverse events such as the prolonged exacerbation of existing symptoms (for example, an increased frequency of unwanted thoughts or nightmares) or the occurrence of new symptoms (for example, anger or self-blame) may lead to dropout, yet there is a surprising scarcity of research exploring the issue (Berk & Parker, 2009). Psychological therapy is traditionally perceived as safe, presenting a low risk of unwanted effects (Nutt & Sharpe, 2008). In reality, the estimated rate of reported side effects is between 3% and 15%, which is of a similar magnitude to that reported for pharmacotherapy (Linden, 2012). However, it is often difficult to draw a distinction between adverse events and time-limited negative experiences inherent to the process of some psychological therapies. This includes the experience of distress provocation, which is inevitable in the process of trauma-focused work.

A survey of psychologists’ attitudes to trauma-focused intervention found that concerns about tolerability and dropout were among the main reasons that psychologists did not use trauma-focused intervention, despite the compelling evidence supporting its use (Becker, Zayfert, & Anderson, 2004). However, only a small number of studies have acknowledged or explored adverse events such as symptom worsening or its influence on dropout in relation to trauma-focused therapy. This is surprising, given that symptom exacerbation has long since been documented in the treatment of PTSD (Pitman et al., 1991; Tarrier et al., 1999b). It also limits our ability to judge how well various therapies were tolerated by PTSD sufferers. An RCT of imagery rehearsal therapy for trauma-related nightmares found that all four participants who actively withdrew from the treatment group had experienced increased negative imagery effects, suggesting a direct relationship between an inability to tolerate the treatment and subsequent dropout (Krakow et al., 2001; Tarrier, Sommerfield, Pilgrim, & Humphreys, 1999). Conversely, a study of 76 individuals found that only 9–21% of participants showed reliable symptom exacerbation, and these individuals were no more likely to drop out of treatment prematurely (Foa, Zoellner, Hembree, & Alvarez-Conrad, 2002). Similarly, an RCT comparing cognitive therapy (without a trauma focus) to imaginal exposure found that symptom worsening affected 10% of participants, with a significantly greater number of these being in the imaginal exposure group; however, this between-group difference was no longer present at follow-up and rates of dropout were similar from both groups (Tarrier et al., 1999).

The studies included in this review usually failed to provide information on adverse events and contained few explanations for dropout, so it is difficult to ascertain the reasons that participants dropped out. It must be acknowledged that symptom improvement is a possible reason for dropout (Szafranski, Smith, Gros, & Resick, 2017). It follows that termination of treatment for this reason would be highest from the most effective treatments (i.e. those with a trauma-focus (Bisson et al., 2013; Bradley et al., 2005; Jonas et al., 2013)). This said, recent studies have found that those who attend more treatment sessions generally obtain more favourable outcomes (Holmes et al., 2019; Rutt, Oehlert, Krieshok, & Lichtenberg, 2018). More transparent reporting of dropout is required to explore this further. Whatever the cause, dropout is a major health and societal concern, which may result in individuals failing to receive optimal treatment (Craske et al., 2006).

4.2. Strengths and limitations

The review followed Cochrane guidelines for the identification of relevant studies; data extraction; and risk assessment (Higgins & Green, 2011). A wide range of psychological therapies for PTSD were considered, which included participants from different countries and backgrounds, who had been exposed to a variety of different traumatic events. Inevitably, there were some limitations. The majority of studies included in the review excluded individuals with comorbidities of substance dependence, psychosis, and severe depression, who may be more likely to drop out of treatment prematurely, as evidenced by particularly high rates of drop out from studies of participants with co-morbid alcohol dependency (Bothwell, Greene, Podolsky, & Jones, 2016; Roberts, Jones, & Bisson, 2016; Zandberg et al., 2016). All included studies were published, resulting in the possibility of publication bias. However, a funnel plot constructed from the data did not show evidence of this being an issue.

Since there is no agreed conceptualization of dropout, this review extracted and meta-analysed data on the number of participants that had left the study at the point of post-treatment assessment to allow the inclusion of data from a maximal number of studies. There may have been some participants who completed a full course of therapy but failed to attend the post-treatment assessment. Equally, there may have been some participants who failed to complete the course of treatment but attended the post-treatment assessment nonetheless. Although this may bias our findings, there are limitations to all methods that we could have adopted to conceptualize dropout.

The review relied on RCT evidence, which is both a strength and a limitation. The methodology may have excluded some potentially high-quality sources of evidence, such as large observational studies and non-randomized controlled effectiveness studies (Bothwell et al., 2016), which could contribute to a more accurate overall assessment of dropout. It may be the case that dropout from clinical trials underestimates the true extent of dropout in routine clinical care on the basis that study teams are motivated to retain participants and often provide incentives for the completion of treatment. Equally, participants may have been more inclined to drop out on the basis of the additional demands of participation in a trial, such as regular completion of research assessments. However, taking a broader approach would risk diluting higher quality sources of evidence with weaker ones. A major weakness was that reasons for dropout were not reported or were poorly reported by most studies and it was not possible to systematically extract and analyse this information.

4.3. Research implications

Bringing together the available evidence on dropout has always been problematic given that there is no agreed definition and studies have conceptualized the phenomenon differently. Agreeing a definition of dropout would advance the field by encouraging the reporting of data that is comparable across trials. A previous study that compared the application of four operational definitions of dropout (therapist judgement, failure to attend the last scheduled appointment, a median-split procedure, and failure to return to therapy after the intake appointment) found that the rate ranged from 17.6% to 53.1%, depending on the definition that was used (Hatchett & Park, 2003). It follows that a framework to guide the standardized collection and documentation of data related to dropout including information on adverse events is needed. There is currently no theoretical concept to guide the evaluation and reporting of dropout and adverse events that occur during psychological therapy, which is needed and would include a standardized list of reasons for dropout. A first step would be for research ethics committees to mandate that future RCTs of psychological treatments routinely collect and report standardized data on dropout, including the reasons for it. When possible, studies should also report on the severity of symptoms at the point that participants drop out from therapy and whether any adverse events occurred (Hembree et al., 2003). Systematic reviews that analyse individual patient data in relation to dropout enable the application of a standardized definition across studies and would advance the field by moving beyond looking at associations between study-level variables and dropout. As noted by previous reviews, there is also a need for the standardized and consistent measurement of treatment acceptability across trials (Lewis, Roberts, Bethell, Robertson, & Bisson, 2018; Simon et al., 2019). Only when we have sufficient knowledge on the reasons for dropout can we be sure that patients are receiving the best possible intervention.

4.4. Clinical implications

Although we cannot be sure that the reasons for dropout are negative, the findings point to the need for careful assessment of the suitability of patients for trauma-focused work. Since there is evidence for the effect of many different modalities of psychological therapy (American Psychological Association, 2017; International Society of Traumatic Stress Studies (ISTSS), 2018; National Institute for Health and Care Excellence (NICE), 2018), a ‘one-size fits all’ approach should be avoided and the evidence-base used to guide shared-decision making between patient and clinician (National Institute for Health and Care Excellence (NICE), 2018, Cloitre, 2015). Enhancing patient choice may improve retention on the basis that individuals are self-selecting treatment approaches that hold personal appeal. Whether or not this ultimately impacts retention and treatment outcomes requires investigation. Since PTSD is a highly heterogeneous condition (Cloitre, 2015; DiMauro, Carter, Folk, & Kashdan, 2014) a greater understanding of dropout has the potential to facilitate the targeted recommendation of existing evidence-based treatments to specific sub-groups of patients. Dropout is clearly a complex phenomenon, which may be best conceptualized as having a multi-faceted aetiology that is likely to vary across different therapies and diagnostic groups. A multi-factorial approach is likely to be required to reduce dropout, such as a stepped care approach that is personalized to include stabilization if necessary and addresses the various barriers to remaining in treatment (Dorrepaal et al., 2013; Zatzick, 2012). Although there is evidence to suggest that trauma-focused therapies can be safely used with a wide range of people with PTSD, including those who may be considered to have contraindications such as psychiatric comorbidities and histories of sexual abuse (Cloitre, Garvert, & Weiss, 2017, van Minnen, Harned, Zoellner, & Mills, 2012, Wagenmans, Van Minnen, Sleijpen, & De Jongh, 2018), further work is needed to determine any possible impact on dropout. Phased therapies have been developed with preparatory work to improve stability before trauma-focused work (Cloitre, Koenen, Cohen, & Han, 2002a). However, there is no consensus as to whether models starting with stabilization are necessary or preferable to directly applying evidence-based trauma-focused interventions (Lahuis, Scholte, Aarts, & Kleber, 2019, Ter Heide, Mooren, & Kleber, 2016; Ter Heide, Mooren, Kleijn, de Jongh, & Kleber, 2011). This approach has been found to result in improved outcomes and greater retention in trauma-focused CBT for PTSD (Bryant et al., 2013). Another option is the introduction of peer support, which has been shown to encourage participants to re-enter treatment and subsequently achieve significant clinical improvement (Hernandez-Tejada, Hamski, & Sánchez-Carracedo, 2017).

Funding Statement

This work was unfunded.

Disclosure statement

No potential conflict of interest was reported by the authors.

References

  1. Acarturk, C., Konuk, E., Cetinkaya, M., Senay, I., Sijbrandij, M., Gulen, B., & Cuijpers, P. (2016). The efficacy of eye movement desensitization and reprocessing for post-traumatic stress disorder and depression among Syrian refugees: Results of a randomized controlled trial. Psychological Medicine, 46(12), 2583–22. [DOI] [PubMed] [Google Scholar]
  2. Adenauer, H., Catani, C., Gola, H., Keil, J., Ruf, M., Schauer, M., & Neuner, F. (2011). Narrative exposure therapy for PTSD increases top-down processing of aversive stimuli – evidence from a randomized controlled treatment trial. BMC Neuroscience, 12(1), 1–13. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Ahmadi, K., Hazrati, M., Ahmadizadeh, M., & Noohi, S. (2015). REM desensitization as a new therapeutic method for post-traumatic stress disorder: A randomized controlled trial. Acta Medica Indonesiana, 47(2), 111–119. [PubMed] [Google Scholar]
  4. Akbarian, F., Bajoghli, H., Haghighi, M., Kalak, N., Holsboer-Trachsler, E., & Brand, S. (2015). The effectiveness of cognitive behavioral therapy with respect to psychological symptoms and recovering autobiographical memory in patients suffering from post-traumatic stress disorder. Neuropsychiatric Disease and Treatment, 11, 395–404. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. American Psychiatric Association . (2013). Diagnostic and statistical manual of mental disorders (5th ed. 4th ed. Text Revision). Washington, DC: Author. [Google Scholar]
  6. American Psychological Association . (2017). Clinical practice guideline for the treatment of Posttraumatic Stress Disorder (PTSD) in adults. Washington, DC: Author. [Google Scholar]
  7. Asukai, N., Saito, A., Tsuruta, N., Kishimoto, J., & Nishikawa, T. (2010). Efficacy of exposure therapy for Japanese patients with posttraumatic stress disorder due to mixed traumatic events: A randomized controlled study. Journal of Traumatic Stress, 23(6), 744–750. [DOI] [PubMed] [Google Scholar]
  8. Beck, J. G., Coffey, S. F., Foy, D. W., Keane, T. M., & Blanchard, E. B. (2009). Group cognitive behavior therapy for chronic posttraumatic stress disorder: An initial randomized pilot study. Behavior Therapy, 40, 82–92. [DOI] [PubMed] [Google Scholar]
  9. Becker, C. B., Zayfert, C., & Anderson, E. (2004). A survey of psychologists’ attitudes towards and utilization of exposure therapy for PTSD. Behaviour Research and Therapy, 42, 277–292. doi: 10.1016/S0005-7967(03)00138-4 [DOI] [PubMed] [Google Scholar]
  10. Berk, M., & Parker, G. (2009). The elephant on the couch: Side-effects of psychotherapy. Australian and New Zealand Journal of Psychiatry, 43(9), 787–794. [DOI] [PubMed] [Google Scholar]
  11. Bichescu, D., Neuner, F., Schauer, M., & Elbert, T. (2007). Narrative exposure therapy for political imprisonment realted chronic posttraumatic stress disorder and depression. Behaviour Research and Therapy, 45, 2212–2220. [DOI] [PubMed] [Google Scholar]
  12. Bisson, J. I., Roberts, N. P., Andrew, M., Cooper, R., & Lewis, C. (2013). Psychological therapies for chronic post-traumatic stress disorder (PTSD) in adults (Review). Cochrane Database of Systematic Reviews, 12, CD003388. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Blanchard, E., Hickling, E. J., Devineni, T., Veazey, C. H., Galovski, T. E., Mundy, E., & Buckley, T. C. (2003). A controlled evaluation of cognitive behaviorial therapy for posttraumatic stress in motor vehicle accident survivors. Behaviour Research and Therapy, 41(1), 79–96. [DOI] [PubMed] [Google Scholar]
  14. Bothwell, L. E., Greene, J. A., Podolsky, S. H., & Jones, D. S. (2016). Assessing the gold standard – Lessons from the history of RCTs. New England Journal of Medical, 374(22), 2175–2181. [DOI] [PubMed] [Google Scholar]
  15. Bradley, R., Greene, J., Russ, E., Dutra, L., & Westen, D. (2005). A multidimensional meta-analysis of psychotherapy for PTSD. American Journal of Psychiatry, 162(2), 214–227. [DOI] [PubMed] [Google Scholar]
  16. Bradshaw, R. A., McDonald, M. J., Grace, R., Detwiler, L., & Austin, K. (2014). A randomized clinical trial of Observed and Experiential Integration (OEI): A simple, innovative intervention for affect regulation in clients with PTSD. Traumatology Traumatology: an International Journal, 20, 161–171. [Google Scholar]
  17. Brom, D., Kleber, R., & Defares, P. (1989). Brief psychotherapy for posttraumatic stress disorders. Journal of Consulting & Clinical Psychology, 57(5), 607–612. [DOI] [PubMed] [Google Scholar]
  18. Bryant, R., Moulds, M. L., Guthrie, R. M., Dang, S. T., & Nixon, R. D. V. (2003). Imaginal exposure alone and imaginal exposure with cognitive restructuring in treatment of posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 71, 706–712. [DOI] [PubMed] [Google Scholar]
  19. Bryant, R. A., Ekasawin, S., Chakrabhand, S., Suwanmitri, S., Duangchun, O., & Chantaluckwong, T. (2011). A randomized controlled effectiveness trial of cognitive behavior therapy for post-traumatic stress disorder in terrorist-affected people in Thailand. World Psychiatry, 10(3), 205–209. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Bryant, R. A., Mastrodomenico, J., Hopwood, S., Kenny, L., Cahill, C., Kandris, E., & Taylor, K. (2013). Augmenting cognitive behaviour therapy for post-traumatic stress disorder with emotion tolerance training: A randomized controlled trial. Psychological Medicine, 43(10), 2153–2160. [DOI] [PubMed] [Google Scholar]
  21. Bryant, R. A., Moulds, M. L., Mastrodomenico, J., Hopwood, S., Felmingham, K., & Nixon, R. D. V. (2007). Who drops out of treatment for post-traumatic stress disorder? Clinical Psychologist, 11(1), 13–15. [Google Scholar]
  22. Buhmann, C., Nordentoft, M., Ekstroem, M., Carlsson, J., & Mortensen, E. L. (2016). The effect of flexible cognitive-behavioural therapy and medical treatment, including antidepressants on post-traumatic stress disorder and depression in traumatised refugees: Pragmatic randomised controlled clinical trial. The British Journal of Psychiatry, 208, 252–259. [DOI] [PubMed] [Google Scholar]
  23. Butollo, W., Karl, R., König, J., & Rosner, R. (2016). A randomized controlled clinical trial of dialogical exposure therapy versus cognitive processing therapy for adult outpatients suffering from PTSD after type I trauma in adulthood. Psychotherapy and Psychosomatics, 85(1), 16–26. [DOI] [PubMed] [Google Scholar]
  24. Capezzani, L., Ostacoli, L., Cavallo, M., Carletto, S., Fernandez, I., Solomon, R., … Cantelmi, T. (2013). EMDR and CBT for cancer patients: Comparative study of effects on PTSD, anxiety, and depression. Journal of EMDR Practice and Research, 7, 134–143. [Google Scholar]
  25. Carletto, S., Borghi, M., Bertino, G., Oliva, F., Cavallo, M.,Hofmann, A., … Ostacoli, L. (2016). Treating post-traumatic stress disorder in patients with multiple sclerosis: A randomized controlled trial comparing the efficacy of eye movement desensitization and reprocessing and relaxation therapy. Frontiers in Psychology, 7, 526. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Carlson, J., Chemtob, C. M., Rusnak, K., Hedlund, N. L., & Muraoka, M. Y. (1998). Eye movement desensitization and reprocessing (EDMR) treatment for combat-related posttraumatic stress disorder. Journal of Traumatic Stress, 11(1), 3–32. [DOI] [PubMed] [Google Scholar]
  27. Castillo, D. T., Chee, C. L., Nason, E., Keller, J., C'de Baca, J., Qualls, C., … Keane, T. M. (2016). Group-delivered cognitive/exposure therapy for PTSD in women veterans: A randomized controlled trial. Psychological Trauma: Theory, Research, Practice and Policy, 8(3), p. No-Specified. [DOI] [PubMed] [Google Scholar]
  28. Chard, K. M. (2005). An evaluation of cognitive processing therapy for the treatment of posttraumatic stress disorder related to childhood sexual abuse. Journal of Consulting and Clinical Psychology, 73(5), 965. [DOI] [PubMed] [Google Scholar]
  29. Cloitre, M. (2015). The “One size fits all” approach to trauma treatment: Should we be satisfied? European Journal of Psychotraumatology, 6(1), 27344. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Cloitre, M., Garvert, D. W., & Weiss, B. J. (2017). Depression as a moderator of STAIR narrative therapy for women with post-traumatic stress disorder related to childhood abuse. European Journal of Psychotraumatology, 8(1), 1377028. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Cloitre, M., Koenen, K. C., Cohen, L. R., & Han, H. (2002a). Skills training in affective and interpersonal regulation followed by exposure: A phase-based treatment for PTSD related to childhood abuse. Journal of Consulting and Clinical Psychology, 70(5), 1067. [DOI] [PubMed] [Google Scholar]
  32. Cloitre, M., Koenen, K. C., Cohen, L. R., & Han, H. (2002b). Skills training in affective and interpersonal regulation followed by exposure: A phase-based treatment for PTSD related to childhood abuse. Journal of Consulting and Clinical Psychology, 70, 1067–1074. [DOI] [PubMed] [Google Scholar]
  33. Cloitre, M., Stovall-McClough, K. C., Nooner, K., Zorbas, P., Cherry, S., Jackson, C. L., … Petkova, E. (2010). Treatment for PTSD related to childhood abuse: A randomized controlled trial. American Journal of Psychiatry, 167, 915–924. [DOI] [PubMed] [Google Scholar]
  34. Cooper, A. A., & Conklin, L. R. (2015). Dropout from individual psychotherapy for major depression: A meta-analysis of randomized clinical trials. Clinical Psychology Review, 40, 57–65. [DOI] [PubMed] [Google Scholar]
  35. Craske, M. G., Roy-Byrne, P., Stein, M. B., Sullivan, G., Hazlett-Stevens, H., Bystritsky, A., & Sherbourne, C. (2006). CBT intensity and outcome for panic disorder in a primary care setting. Behavior Therapy, 37(2), 112–119. [DOI] [PubMed] [Google Scholar]
  36. Devilly, G., & Foa, E. (2001). Comments on Tarrier et al’s (1999) study and the investigation of exposure and cognitive therapy. Journal of Consulting and Clinical Psychology, 69, 114–116. [DOI] [PubMed] [Google Scholar]
  37. Devilly, G., Spence, S., & Rapee, R. (1998). Statistical and reliable change with eye movement desensitization and reprocessing: Treating trauma within a veteran population. Behavior Therapy, 29, 435–455. [Google Scholar]
  38. Devilly, G. J., & Spence, S. H. (1999). The relative efficacy and treatment distress of EMDR and a cognitive-behavior trauma treatment protocol in the amelioration of posttraumatic stress disorder. Journal of Anxiety Disorders, 13(1–2), 131–157. [DOI] [PubMed] [Google Scholar]
  39. DiMauro, J., Carter, S., Folk, J. B., & Kashdan, T. B. (2014). A historical review of trauma-related diagnoses to reconsider the heterogeneity of PTSD. Journal of Anxiety Disorders, 28(8), 774–786. [DOI] [PubMed] [Google Scholar]
  40. Dorrepaal, E., Thomaes, K., Hoogendoorn, A. W., Veltman, D. J., Draijer, N., & van Balkom, A. J. L. M. (2014). Evidence-based treatment for adult women with child abuse-related complex PTSD: A quantitative review. European Journal of Psychotraumatology, 5(1), 23613. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Dorrepaal, E., Thomaes, K., Smit, J. H., van Balkom, A. J. L. M., Veltman, D. J., Hoogendoorn, A. W., & Draijer, N. (2012). Stabilizing group treatment for complex posttraumatic stress disorder related to child abuse based on psychoeducation and cognitive behavioural therapy: A multisite randomized controlled trial. Psychotherapy and Psychosomatics, 81, 217–225. [DOI] [PubMed] [Google Scholar]
  42. Dorrepaal, E., Thomaes, K., Smit, J. H., Veltman, D. J., Hoogendoorn, A. W., van Balkom, A. J. L. M., & Draijer, N. (2013). Treatment compliance and effectiveness in complex PTSD patients with co-morbid personality disorder undergoing stabilizing cognitive behavioral group treatment: A preliminary study. European Journal of Psychotraumatology, 4(1), 21171. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Duffy, M., Gillespie, K., & Clark, D. (2007). Post-traumatic stress disorder in the context of terrorism and other civil conflict in Northern Ireland: Randomised controlled trial. British Medical Journal, 334, 1147–1150. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Dunne, R. L., Kenardy, J., & Sterling, M. (2012). A randomized controlled trial of cognitive-behavioral therapy for the treatment of PTSD in the context of chronic whiplash. The Clinical Journal of Pain, 28(9), 755–765. [DOI] [PubMed] [Google Scholar]
  45. Echeburua, E., Zubizarreta, I., & Sarasua, B. (1997). Psychological treatment of chronic posttraumatic stress disorder in victims of sexual aggression. Behavior Modification, 21, 433–456. [DOI] [PubMed] [Google Scholar]
  46. Ehlers, A., Clark, D. M., Hackmann, A., McManus, F., & Fennell, M. (2005). Cognitive therapy for post-traumatic stress disorder: Development and evaluation. Behaviour Research and Therapy, 43, 413–431. [DOI] [PubMed] [Google Scholar]
  47. Ehlers, A., Clark, D. M., Hackmann, A., McManus, F., Fennell, M., Herbert, C., & Mayou, R. (2003). A randomized controlled trial of cognitive therapy, a self-help booklet, and repeated assessments as early interventions for posttraumatic stress disorder. Archives of General Psychiatry, 60(10), 1024–1032. [DOI] [PubMed] [Google Scholar]
  48. Ehlers, A., Hackmann, A., Grey, N., Wild, J., Liness, S., Albert, I., & Clark, D. M. (2014). A randomized controlled trial of 7-day intensive and standard weekly cognitive therapy for PTSD and emotion-focused supportive therapy. American Journal of Psychiatry, 171, 294–304. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Falsetti, S., Resnick, H., & Davis, J. (2008). Multiple channel exposure therapy for women with PTSD and comorbid panic attacks. Cognitive Behaviour Therapy, 37, 117–130. [DOI] [PubMed] [Google Scholar]
  50. Fecteau, G., & Nicki, R. (1999). Cognitive behavioural treatment of post traumatic stress disorder after motor vehicle accident. Behavioural & Cognitive Psychotherapy, 27(3), 201–214. [Google Scholar]
  51. Feske, U. (2008). Treating low-income and minority women with posttraumatic stress disorder a pilot study comparing prolonged exposure and treatment as usual conducted by community therapists. Journal of Interpersonal Violence, 23(8), 1027–1040. [DOI] [PubMed] [Google Scholar]
  52. Foa, E., Dancu, C. V., Hembree, E. A., Jaycox, L. H., Meadows, E. A., & Street, G. P. (1999). A comparison of exposure therapy, stress inoculation training, and their combination for reducing posttraumatic stress disorder in female assault victims. Journal of Consulting and Clinical Psychology, 67(2), 194–200. [DOI] [PubMed] [Google Scholar]
  53. Foa, E., Hembree, E. A., Cahill, S. P., Rauch, S. A. M., Riggs, D. S., Feeny, N. C., & Yadin, E. (2005). Randomized trial of prolonged exposure for posttraumatic stress disorder with and without cognitive restructuring: Outcome at academic and community clinics. Journal of Consulting and Clinical Psychology, 73, 953–964. [DOI] [PubMed] [Google Scholar]
  54. Foa, E., McLean, C. P., Zang, Y., Rosenfield, D., Yadin, E., Yarvis, J. S., & Peterson, A. L. (2018). Effect of prolonged exposure therapy delivered over 2 weeks vs 8 weeks vs present-centered therapy on PTSD symptom severity in military personnel: A randomized clinical trial. Jama, 319, 354–364. [DOI] [PMC free article] [PubMed] [Google Scholar]
  55. Foa, E., Rothbaum, B. O., Riggs, D. S., & Murdock, T. B. (1991). Treatment of posttraumatic stress disorder in rape victims: A comparison between cognitive-behavioral procedures and counseling. Journal of Consulting and Clinical Psychology, 59(5), 715–723. [DOI] [PubMed] [Google Scholar]
  56. Foa, E. B., Keane, T. M., Friedman, M. J., & Cohen, J. A. (Eds.). (2008). Effective treatments for PTSD: Practice guidelines from the international society for traumatic stress studies. Guilford Press. [Google Scholar]
  57. Foa, E. B., Zoellner, L. A., Hembree, E. A., & Alvarez-Conrad, J. (2002). Does imaginal exposure exacerbate PTSD symptoms? Journal of Consulting and Clinical Psychology, 70(4). doi: 10.1037/0022-006X.70.4.1022 [DOI] [PubMed] [Google Scholar]
  58. Fonzo, G., Goodkind, M. S., Oathes, D. J., Zaiko, Y. V., Harvey, M., Peng, K. K., … Etkin, A. (2017). PTSD psychotherapy outcome predicted by brain activation during emotional reactivity and regulation. American Journal of Psychiatry, 174, 1163–1174. [DOI] [PMC free article] [PubMed] [Google Scholar]
  59. Forbes, D., Lloyd, D., Nixon, R. D. V., Elliott, P., Varker, T., Perry, D., … Creamer, M. (2012). A multisite randomized controlled effectiveness trial of cognitive processing therapy for military-related posttraumatic stress disorder. Journal of Anxiety Disorders, 26(3), 442–452. [DOI] [PubMed] [Google Scholar]
  60. Ford, J. D., Chang, R., Levine, J., & Zhang, W. (2013). Randomized clinical trial comparing affect regulation and supportive group therapies for victimization-related PTSD with incarcerated women. Behavior Therapy, 44(2), 262–276. [DOI] [PubMed] [Google Scholar]
  61. Ford, J. D., Steinberg, K. L., & Zhang, W. (2011). A randomized clinical trial comparing affect regulation and social problem-solving psychotherapies for mothers with victimization-related PTSD. Behavior Therapy, 42(4), 560–578. [DOI] [PubMed] [Google Scholar]
  62. Galovski, T. E., Blain, L. M., Mott, J. M., Elwood, L., & Houle, T. (2012). Manualized therapy for PTSD: Flexing the structure of cognitive processing therapy. Journal of Consulting and Clinical Psychology, 80(6), 968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  63. Gamito, P., Oliveira, J., Rosa, P., Morais, D., Duarte, N., Oliveira, S., & Saraiva, T. (2010). PTSD elderly war veterans: A clinical controlled pilot study. Cyberpsychology, Behavior and Social Networking, 13(1), 43–48. [DOI] [PubMed] [Google Scholar]
  64. Gersons, B. P., Carlier, I. V., Lamberts, R. D., & Van der Kolk, B. A. (2000). Randomized clinical trial of brief eclectic psychotherapy for police officers with posttraumatic stress disorder. Journal of Traumatic Stress, 13(2), 333–347. [DOI] [PubMed] [Google Scholar]
  65. Goetter, E. M., Bui, E., Ojserkis, R. A., Zakarian, R. J., Brendel, R. W., & Simon, N. M. (2015). A systematic review of dropout from psychotherapy for posttraumatic stress disorder among Iraq and Afghanistan combat veterans. Journal of Traumatic Stress, 28(5), 401–409. [DOI] [PubMed] [Google Scholar]
  66. Gray, R., Budden-Potts, D., & Bourke, F. (2017). Reconsolidation of traumatic memories for PTSD: A randomized controlled trial of 74 male veterans. Psychotherapy Research, 1–19. [DOI] [PubMed] [Google Scholar]
  67. Hatchett, G. T., & Park, H. L. (2003). Comparison of four operational definitions of premature termination. Psychotherapy: Theory, Research, Practice, Training, 40(3), 226. [Google Scholar]
  68. Hembree, E. A., Foa, E. B., Dorfan, N. M., Street, G. P., Kowalski, J., & Tu, X. (2003). Do patients drop out prematurely from exposure therapy for PTSD? Journal of Traumatic Stress, 16(6), 555–562. [DOI] [PubMed] [Google Scholar]
  69. Hensel-Dittmann, D., Schauer, M., Ruf, M., Catani, C., Odenwald, M., Elbert, T., & Neuner, F. (2011). Treatment of traumatized victims of war and torture: A randomized controlled comparison of narrative exposure therapy and stress inoculation training. Psychotherapy and Psychosomatics, 80(6), 345–352. [DOI] [PubMed] [Google Scholar]
  70. Hernandez-Tejada, M. A., Hamski, S., & Sánchez-Carracedo, D. (2017). Incorporating peer support during in vivo exposure to reverse dropout from prolonged exposure therapy for posttraumatic stress disorder: Clinical outcomes. The International Journal of Psychiatry in Medicine, 52(4–6), 366–380. [DOI] [PubMed] [Google Scholar]
  71. Higgins, J., & Green, S. (2011). Cochrane handbook for systematic reviews of interventions. The Cochrane Collaboration. Retrieved from www.cochrane-handbook.org
  72. Higgins, J. P., Altman, D. G., Gotzsche, P. C., Juni, P., Moher, D., Oxman, A. D., … Sterne, J. A. C. (2011). The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. BMJ, 343, d5928. [DOI] [PMC free article] [PubMed] [Google Scholar]
  73. Hinton, D., Chhean, D., Pich, V., Safren, S. A., Hofmann, S. G., & Pollack, M. H. (2005). A randomised controlled trial of cognitive behaviour therapy for Cambodian refugees with treatment resistant PTSD and panic attacks: A cross over design. Journal of Traumatic Stress, 18, 617–629. [DOI] [PubMed] [Google Scholar]
  74. Hinton, D. E., Hofmann, S. G., Rivera, E., Otto, M. W., & Pollack, M. H. (2011). Culturally adapted CBT (CA-CBT) for Latino women with treatment-resistant PTSD: A pilot study comparing CA-CBT to applied muscle relaxation. Behaviour Research and Therapy, 49(4), 275–280. [DOI] [PubMed] [Google Scholar]
  75. Hogberg, G., Pagani, M., Sundin, O., Soares, J., Aberg-Wistedt, A., Tarnell, B., & Hallstrom, T. (2007). On treatment with eye movement desensitization and reprocessing of chronic post-traumatic stress disorder in public transportation workers – a randomized controlled trial. Nordic Journal of Psychiatry, 61(1), 54–60. [DOI] [PubMed] [Google Scholar]
  76. Hollifield, M., Sinclair-Lian, N., Warner, T. D., & Hammerschlag, R. (2007). Acupuncture for posttraumatic stress disorder. The Journal of Nervous and Mental Disease, 195(6), 504–513. [DOI] [PubMed] [Google Scholar]
  77. Holmes, S. C., Johnson, C. M., Suvak, M. K., Sijercic, I., Monson, C. M., & Wiltsey Stirman, S. (2019). Examining patterns of dose response for clients who do and do not complete cognitive processing therapy. Journal of Anxiety Disorders, 68, 102120. [DOI] [PMC free article] [PubMed] [Google Scholar]
  78. Imel, Z. E., Laska, K., Jakupcak, M., & Simpson, T. L. (2013). Meta-analysis of dropout in treatments for posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 81(3), 394. [DOI] [PMC free article] [PubMed] [Google Scholar]
  79. International Society of Traumatic Stress Studies (ISTSS) . (2018). New ISTSS Prevention and Treatment Guidelines [Online]. Retrieved from http://www.istss.org/treating-trauma/new-istss-guidelines.aspx
  80. Ironson, G., Freund, B., Strauss, J. L., & Williams, J. (2002). Comparison of two treatments for traumatic stress: A community based study of EMDR and prolonged exposure. Journal of Clinical Psychology, 58, 113–128. [DOI] [PubMed] [Google Scholar]
  81. Ivarsson, D., Blom, M., Hesser, H., Carlbring, P., Enderby, P., Nordberg, R., & Andersson, G. (2014). Guided internet-delivered cognitive behavior therapy for post-traumatic stress disorder: A randomized controlled trial. Internet Interventions, 1, 33–40. [Google Scholar]
  82. Jacob, N., Neuner, F., Maedl, A., Schaal, S., & Elbert, T. (2014). Dissemination of psychotherapy for trauma spectrum disorders in postconflict settings: A randomized controlled trial in Rwanda. Psychotherapy and Psychosomatics, 83, 354–363. [DOI] [PubMed] [Google Scholar]
  83. Jensen, J. (1994). An investigation of eye movement desensitisation and reprocessing as a treatment for posttraumatic stress disorder symptoms of Vietnam combat veterans. Behavior Therapy, 25, 311–325. [Google Scholar]
  84. Johnson, D., Johnson, N. L., Perez, S. K., Palmieri, P. A., & Zlotnick, C. (2016). Comparison of adding treatment of PTSD during and after shelter stay to standard care in residents of battered women’s shelters: Results of a randomized clinical trial. Journal of Traumatic Stress, 29, 365–373. [DOI] [PMC free article] [PubMed] [Google Scholar]
  85. Johnson, D. M., Zlotnick, C., & Perez, S. (2011). Cognitive behavioral treatment of PTSD in residents of battered women’s shelters: Results of a randomized clinical trial. Journal of Consulting and Clinical Psychology, 79(4), 542. [DOI] [PMC free article] [PubMed] [Google Scholar]
  86. Jonas, D. E., Cusack, K., Forneris, C. A., Wilkins, T. M., Sonis, J., Middleton, J. C., … Olmsted, K. R. (2013). Psychological and pharmacological treatments for adults with posttraumatic stress disorder (PTSD). In: Comparative Effectiveness Review No. 92. US Agency for Healthcare Research and Quality. [PubMed]
  87. Karatzias, T., Power, K., Brown, K., McGoldrick, T., Begum, M., Young, J., … Adams, S. (2011). A controlled comparison of the effectiveness and efficiency of two psychological therapies for posttraumatic stress disorder: Eye movement desensitization and reprocessing vs. emotional freedom techniques. The Journal of Nervous and Mental Disease, 199, 372–378. [DOI] [PubMed] [Google Scholar]
  88. Keane, T., Fairbank, J. A., Caddell, J. M., & Zimering, R. T. (1989). Implosive (flooding) therapy reduces symptoms of PTSD in Vietnam combat veterans. Behavior Therapy, 20(2), 245–260. [Google Scholar]
  89. Kessler, R. C. (2000). Posttraumatic stress disorder: The burden to the individual and to society. Journal of Clinical Psychiatry., 61(5), 4–14. [PubMed] [Google Scholar]
  90. Krakow, B., Hollifield, M., Johnston, L., Koss, M., Schrader, R., Warner, T. D., & Prince, H. (2001). Imagery rehearsal therapy for chronic nightmares in sexual assault survivors with posttraumatic stress disorder: A randomized controlled trial. JAMA, 286(5), 537–545. [DOI] [PubMed] [Google Scholar]
  91. Krupnick, J. L., Green, B. L., Stockton, P., Miranda, J., Krause, E., & Mete, M. (2008). Group interpersonal psychotherapy for low-income women with posttraumatic stress disorder. Psychotherapy Research, 18(5), 497–507. [DOI] [PubMed] [Google Scholar]
  92. Kubany, E., Hill, E., & Owens, J. (2004). Cognitive trauma therapy for battered women with PTSD (CTT-BW). Journal of Consulting and Clinical Psychology, 72(1), 3–18. [DOI] [PubMed] [Google Scholar]
  93. Kubany, E., Hill, E. E., & Owens, J. A. (2003). Cognitive trauma therapy for battered women with PTSD: Preliminary findings. Journal of Traumatic Stress, 16, 81–91. [DOI] [PubMed] [Google Scholar]
  94. Lahuis, A. M., Scholte, W. F., Aarts, R., & Kleber, R. J. (2019). Undocumented asylum seekers with posttraumatic stress disorder in the Netherlands. European Journal of Psychotraumatology, 10(1), 1605281. [DOI] [PMC free article] [PubMed] [Google Scholar]
  95. Laugharne, J., Kullack, C., Lee, C. W., McGuire, T., Brockman, S., Drummond, P. D., & Starkstein, S. (2016). Amygdala volumetric change following psychotherapy for posttraumatic stress disorder. The Journal of Neuropsychiatry and Clinical Neurosciences, 28, 312–318. [DOI] [PubMed] [Google Scholar]
  96. Lee, C., Gavriel, H., Drummond, P., Richards, J., & Greenwald, R. (2002). Treatment of PTSD: Stress inoculation training with prolonged exposure compared to EMDR. Journal of Clinical Psychology, 58, 1071–1089. [DOI] [PubMed] [Google Scholar]
  97. Lewis, C., Roberts, N. P., Bethell, A., Robertson, L., & Bisson, J. I. (2018). Internet-based cognitive and behavioural therapies for post-traumatic stress disorder (PTSD) in adults. Cochrane Database of Systematic Reviews, 12, Art. No.: CD011710. [DOI] [PMC free article] [PubMed] [Google Scholar]
  98. Lewis, C. E., Farewell, D., Groves, V., Kitchiner, N. J., Roberts, N. P., Vick, T., & Bisson, J. I. (2017). Internet-based guided self-help for posttraumatic stress disorder (PTSD): Randomized controlled trial. Depression and Anxiety, 34(6), 555–565. [DOI] [PubMed] [Google Scholar]
  99. Lindauer, R. J., Gersons, B. P., van Meijel, E. P., Blom, K., Carlier, I. V., Vrijlandt, I., & Olff, M. (2005). Effects of brief eclectic psychotherapy in patients with posttraumatic stress disorder: Randomized clinical trial. Journal of Traumatic Stress, 18(3), 205–212. [DOI] [PubMed] [Google Scholar]
  100. Linden, M. (2012). How to define, find and classify side effects in psychotherapy: From unwanted events to adverse treatment reactions. Clinical Psychology and Psychotherapy, Published Online in Wiley Online Library. doi: 10.1002/cpp.1765, [DOI] [PubMed] [Google Scholar]
  101. Littleton, H., Grills, A. E., Kline, K. D., Schoemann, A. M., & Dodd, J. C. (2016). The From Survivor to Thriver program: RCT of an online therapist-facilitated program for rape-related PTSD. Journal of Anxiety Disorders, 43, 41–51. [DOI] [PMC free article] [PubMed] [Google Scholar]
  102. Litz, B. T., Engel, C. C., Bryant, R. A., & Papa, A. (2007). A randomized, controlled proof-of-concept trial of an Internet-based, therapist-assisted self-management treatment for posttraumatic stress disorder. American Journal of Psychiatry, 164, 1676–1683. [DOI] [PubMed] [Google Scholar]
  103. Marcus, S., Marquis, P., & Sakai, C. (1997). Controlled study of treatment of PTSD using EMDR in an HMO setting. Psychotherapy Theory, Research and Practice, 34, 307–315. [Google Scholar]
  104. Markowitz, J., Petkova, E., Neria, Y., Van Meter, P. E., Zhao, Y., Hembree, E., & Marshall, R. D. (2015). Is exposure necessary? A randomized clinical trial of interpersonal psychotherapy for PTSD. American Journal of Psychiatry, 172, 430–440. [DOI] [PMC free article] [PubMed] [Google Scholar]
  105. Marks, I., Lovell, K., Noshirvani, H., Livanou, M., & Thrasher, S. (1998). Treatment of posttraumatic stress disorder by exposure and/or cognitive restructuring: A controlled study. Archives of General Psychiatry, 55(4), 317–325. [DOI] [PubMed] [Google Scholar]
  106. McDonagh, A., Friedman, M., McHugo, G., Ford, J., Sengupta, A., Mueser, K., … Descamps, M. (2005). Randomized controlled trial of cognitive-behavioural therapy for chronic posttraumatic stress disorder in adult female survivors of childhood sexual abuse. Journal of Consulting and Clinical Psychology, 73, 515–524. [DOI] [PubMed] [Google Scholar]
  107. McLay, R., Baird, A., Webb-Murphy, J., Deal, W., Tran, L., Anson, H., … Johnston, S. (2017). A randomized, head-to-head study of virtual reality exposure therapy for posttraumatic stress disorder. Cyberpsychology, Behavior, and Social Networking, 20, 218–224. [DOI] [PubMed] [Google Scholar]
  108. McLay, R., Wood, D. P., Webb-Murphy, J. A., Spira, J. L., Wiederhold, M. D., Pyne, J. M., & Wiederhold, B. K. (2011). A randomized, controlled trial of virtual reality-graded exposure therapy for post-traumatic stress disorder in active duty service members with combat-related post-traumatic stress disorder. Cyberpsychology, Behavior and Social Networking, 14, 223–229. [DOI] [PubMed] [Google Scholar]
  109. Monson, C., Fredman, S. J., Macdonald, A., Pukay-Martin, N. D., Resick, P. A., & Schnurr, P. P. (2012). Effect of cognitive-behavioral couple therapy for PTSD: A randomized controlled trial. Jama, 308, 700–709. [DOI] [PMC free article] [PubMed] [Google Scholar]
  110. Monson, C., Schnurr, P. P., Resick, P. A., Friedman, M. J., Young-Xu, Y., & Stevens, S. P. (2006). Cognitive processing therapy for veterans with military related posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 74, 898–907. [DOI] [PubMed] [Google Scholar]
  111. Morath, J., Moreno-Villanueva, M., Hamuni, G., Kolassa, S., Ruf-Leuschner, M., Schauer, M., & Kolassa, I.-T. (2014). Effects of psychotherapy on DNA strand break accumulation originating from traumatic stress. Psychotherapy and Psychosomatics, 83, 289–297. [DOI] [PubMed] [Google Scholar]
  112. Mueser, K. T., Rosenburg, S. D., Xie, H., Jankowski, M. K., Bolton, E. E., Lu, W., … Rosenburg, H. J. (2008). A randomized controlled trial of cognitive-behavioral treatment for posttraumatic stress disorder in severe mental illness. Journal of Consulting and Clinical Psychology, 76, 259–271. [DOI] [PMC free article] [PubMed] [Google Scholar]
  113. Nacasch, N., Foa, E. B., Huppert, J. D., Tzur, D., Fostick, L., Dinstein, Y., … Zohar, J. (2011). Prolonged exposure therapy for combat- and terror-related posttraumatic stress disorder: A randomized control comparison with treatment as usual NCT00229372. The Journal of Clinical Psychiatry, 72, 1174–1180. [DOI] [PubMed] [Google Scholar]
  114. National Institute for Health and Care Excellence (NICE) . (2018). Post-traumatic stress disorder (NICE guideline NG116). Retrieved from https://www.nice.org.uk/guidance/ng116 [PubMed]
  115. Neuner, F., Kurreck, S., Ruf, M., Odenwald, M., Elbert, T., & Schauer, M. (2010). A randomized controlled pilot study. Can asylum seekers with posttraumatic stress disorder be successfully treated? Cognitive Behaviour Therapy, 39(2), 81–91. [DOI] [PubMed] [Google Scholar]
  116. Neuner, F., Onyut, P. L., Ertl, V., Odenwald, M., Schauer, E., & Elbert, T. (2008). Treatment of posttraumatic stress disorder by trained lay counselors in an African refugee settlement: A randomized controlled trial. Journal of Consulting and Clinical Psychology, 76(4), 686. [DOI] [PubMed] [Google Scholar]
  117. Neuner, F., Schauer, M., Klaschik, C., Karunakara, U., & Elbert, T. (2004). A comparison of narrative exposure therapy, supportive counselling, and psychoeducation for treating posttraumatic stress disorder in an African refugee settlement. Journal of Consulting and Clinical Psychology, 72(4), 579–587. [DOI] [PubMed] [Google Scholar]
  118. Nijdam, M. J., Gersons, B. P. R., Reitsma, J. B., de Jongh, A., & Olff, M. (2012). Brief eclectic psychotherapy v. eye movement desensitisation and reprocessing therapy for post-traumatic stress disorder: Randomised controlled trial. The British Journal of Psychiatry, 200(3), 224–231. [DOI] [PubMed] [Google Scholar]
  119. Nutt, D. J., & Sharpe, M. (2008). Uncritical positive regard? Issues in the efficacy and safety of psychotherapy. Journal of Psychopharmacology, 22(1), 3. [DOI] [PubMed] [Google Scholar]
  120. Pacella, M. L., Armelie, A., Boarts, J., Wagner, G., Jones, T., Feeny, N., & Delahanty, D. L. (2012). The impact of prolonged exposure on PTSD symptoms and associated psychopathology in people living with HIV: A randomized test of concept. AIDS and Behavior, 16(5), 1327–1340. [DOI] [PMC free article] [PubMed] [Google Scholar]
  121. Paunovic, N. (2011). Exposure inhibition therapy as a treatment for chronic posttraumatic stress disorder: A controlled pilot study. Psychology, 2(6), 605. [Google Scholar]
  122. Peniston, E. G., & Kulkosky, P. J. (1991). Alpha-theta brainwave neurofeedback for Vietnam veterans with combat-related post-traumatic stress disorder. Medical Psychotherapy, 4(1), 47–60. [Google Scholar]
  123. Pitman, R. K., Altman, B., Greenwald, E., Longpre, R. E., Macklin, M. L., Poire, R. E., & Steketee, G. S. (1991). Psychiatric complications during flooding therapy for posttraumatic stress disorder. The Journal of Clinical Psychiatry, 52(1), 17–20. [PubMed] [Google Scholar]
  124. Power, K., McGoldrick, T., Brown, K., Buchanan, R., Sharp, D., Swanson, V., & Karatzias, A. (2002). A controlled comparison of eye movement desensitisation and reprocessing versus exposure plus cognitive restructuring versus waiting list in the treatment of post-traumatic stress disorder. Clinical Psychology and Psychotherapy, 9, 229–318. [Google Scholar]
  125. Rauch, S., King, A. P., Abelson, J., Tuerk, P. W., Smith, E., Rothbaum, B. O., … Liberzon, I. (2015). Biological and symptom changes in posttraumatic stress disorder treatment: A randomized clinical trial. Depression and Anxiety, 32, 204–212. [DOI] [PubMed] [Google Scholar]
  126. Ready, D. J., Gerardi, R. J., Backscheider, A. G., Mascaro, N., & Rothbaum, B. O. (2010). Comparing virtual reality exposure therapy to present centred therapy with 11 US Vietnam Veterans with PTSD cyberpsychology. Behavior and Social Networking, 13(1), 49–54. [DOI] [PubMed] [Google Scholar]
  127. Reger, G., Koenen-Woods, P., Zetocha, K., Smolenski, D. J., Holloway, K. M., Rothbaum, B. O., & Gahm, G. A. (2016). Randomized controlled trial of prolonged exposure using imaginal exposure vs. virtual reality exposure in active duty soldiers with deployment-related posttraumatic stress disorder (PTSD). Journal of Consulting and Clinical Psychology, 84, 946–959. [DOI] [PubMed] [Google Scholar]
  128. Resick, P., Nishith, P., Weaver, T. L., Astin, M. C., & Feuer, C. A. (2002). A comparison of cognitive-processing therapy with prolonged exposure and a waiting condition for the treatment of chronic posttraumatic stress disorder in female rape victims. Journal of Consulting and Clinical Psychology, 70(4), 867–879. [DOI] [PMC free article] [PubMed] [Google Scholar]
  129. Resick, P. A., Wachen, J. S., Dondanville, K. A., Pruiksma, K. E., Yarvis, J. S., Peterson, A. L., … Young-McCaughan, S. (2017). Effect of group vs individual cognitive processing therapy in active-duty military seeking treatment for posttraumatic stress disorder: A randomized clinical trial. JAMA Psychiatry (Chicago, IL), 74(1), 28–36. [DOI] [PubMed] [Google Scholar]
  130. Resick, P. A., Wachen, J. S., Mintz, J., Young-McCaughan, S., Roache, J. D., Borah, A. M., & Peterson, A. L. (2015). A randomized clinical trial of group cognitive processing therapy compared with group present-centered therapy for PTSD among active duty military personnel. Journal of Consulting and Clinical Psychology, 83(6), 1058. Epub ahead of print. [DOI] [PubMed] [Google Scholar]
  131. Roberts, N. P., Jones, N., & Bisson, J. I. (2016). Psychological interventions for post-traumatic stress disorder and comorbid substance use disorder. Cochrane Database of Systematic Reviews, (4), Art. No.: CD010204. doi: 10.1002/14651858.CD010204.pub2 [DOI] [PMC free article] [PubMed] [Google Scholar]
  132. Rothbaum, B. (1997). A controlled study of eye movement desensitization and reprocessing in the treatment of posttraumatic stress disordered sexual assault victims. Bulletin of the Menninger Clinic, 61(61), 317–334. [PubMed] [Google Scholar]
  133. Rothbaum, B., Astin, M. C., & Marsteller, F. (2005). Prolonged exposure versus eye movement desensitisation and reprocessing (EMDR) for PTSD rape victims. Journal of Traumatic Stress, 18, 607–616. [DOI] [PubMed] [Google Scholar]
  134. Rutt, B. T., Oehlert, M. E., Krieshok, T. S., & Lichtenberg, J. W. (2018). Effectiveness of cognitive processing therapy and prolonged exposure in the Department of Veterans affairs. Psychological Reports, 121(2), 282–302. [DOI] [PubMed] [Google Scholar]
  135. Sautter, F. J., Glynn, S. M., Cretu, J. B., Senturk, D., & Vaught, A. S. (2015). Efficacy of structured approach therapy in reducing PTSD in returning veterans: A randomized clinical trial. Psychological Services, 12(3), 199–212. [DOI] [PubMed] [Google Scholar]
  136. Scheck, M., Schaeffer, J. A., & Gillette, C. (1998). Brief psychological intervention with traumatized young women: The efficacy of eye movement desensitisation and reprocessing. Journal of Traumatic Stress, 11, 25–44. [DOI] [PubMed] [Google Scholar]
  137. Schnurr, P., Friedman, M. J., Engel, C. C., Foa, E. B., Shea, M. T., Chow, B. K., … Bernardy, N. (2007). Cognitive behavioural therapy for posttraumatic stress disorder in women. JAMA, 28, 820–830. [DOI] [PubMed] [Google Scholar]
  138. Schnurr, P., Friedman, M. J., Foy, D. W., Shea, M. T., Hsieh, F. Y., Lavori, P. W., & Bernardy, N. C. (2003). Randomized trial of trauma-focused group therapy for posttraumatic stress disorder. Archives of General Psychiatry, 60, 481–489. [DOI] [PubMed] [Google Scholar]
  139. Schnyder, U., Ehlers, A., Elbert, T., Foa, E. B., Gersons, B. P. R., Resick, P. A., … Cloitre, M. (2015). Psychotherapies for PTSD: What do they have in common? European Journal of Psychotraumatology, 6(1), 28186. [DOI] [PMC free article] [PubMed] [Google Scholar]
  140. Schnyder, U., Müller, J., Maercker, A., & Wittmann, L. (2011). Brief eclectic psychotherapy for PTSD: A randomized controlled trial. Journal of Clinical Psychiatry, 72(4), 564–566. doi: 10.4088/JCP.09m05440blu [DOI] [PubMed] [Google Scholar]
  141. Schottenbauer, M. A., Glass, C. R., Arnkoff, D. B., Tendick, V., & Gray, S. H. (2008). Nonresponse and dropout rates in outcome studies on PTSD: Review and methodological considerations. Psychiatry, 71(2), 134–168. [DOI] [PubMed] [Google Scholar]
  142. Simon, N., McGillivray, L., Roberts, N. P., Barawi, K., Lewis, C. E., & Bisson, J. I. (2019). Acceptability of internet-based cognitive behavioural therapy (i-CBT) for post-traumatic stress disorder (PTSD): A systematic review. European Journal of Psychotraumatology, 10(1), 1646092. [DOI] [PMC free article] [PubMed] [Google Scholar]
  143. Sloan, D., Marx, B. P., Bovin, M. J., Feinstein, B. A., & Gallagher, M. W. (2012). Written exposure as an intervention for PTSD: A randomized clinical trial with motor vehicle accident survivors. Behaviour Research and Therapy, 50(10), 627–635. [DOI] [PMC free article] [PubMed] [Google Scholar]
  144. Sloan, D., Marx, B. P., Lee, D. J., & Resick, P. A. (2018). A brief exposure-based treatment vs cognitive processing therapy for posttraumatic stress disorder: A randomized noninferiority clinical trial. JAMA Psychiatry, 75, 233. [DOI] [PMC free article] [PubMed] [Google Scholar]
  145. Spence, J., Titov, N., Dear, B. F., Johnston, L., Solley, K., Lorian, C., … Schwenke, G. (2011). Randomised controlled trial of internet delivered cognitive behavioural therapy for posttraumatic stress disorder. Depression and Anxiety, 28, 541–550. [DOI] [PubMed] [Google Scholar]
  146. StataCorp . (2013). Stata statistical software: Release 13. College Station, TX: Author. [Google Scholar]
  147. Stenmark, H., Catani, C., Neuner, F., Elbert, T., & Holen, A. (2013). Treating PTSD in refugees and asylum seekers within the general health care system. A randomized controlled multicenter study. Behaviour Research and Therapy, 51, 641–647. [DOI] [PubMed] [Google Scholar]
  148. Suris, A., Link-Malcolm, J., Chard, K., Ahn, C., & North, C. (2013). A randomized clinical trial of cognitive processing therapy for veterans with PTSD related to military sexual trauma. Journal of Traumatic Stress, 26, 28–37. [DOI] [PubMed] [Google Scholar]
  149. Szafranski, D. D., Smith, B. N., Gros, D. F., & Resick, P. A. (2017). High rates of PTSD treatment dropout: A possible red herring? Journal of Anxiety Disorders, 47, 91–98. [DOI] [PubMed] [Google Scholar]
  150. Tarrier, N., Pilgrim, H., Sommerfield, C., Faragher, B., Reynolds, M., Graham, E., & Barrowclough, C. (1999a). A randomized trial of cognitive therapy and imaginal exposure in the treatment of chronic posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 67(1), 13–18. [DOI] [PubMed] [Google Scholar]
  151. Tarrier, N., Pilgrim, H., Sommerfield, C., Faragher, B., Reynolds, M., Graham, E., & Barrowclough, C. (1999b). A randomized controlled trial of cognitive therapy and imaginal exposure in the treatment of chronic posttraumatic stress disorder. Journal of Consulting & Clinical Psychology, 67, 13–18. doi: 10.1037/0022-006X.67.1.13 [DOI] [PubMed] [Google Scholar]
  152. Tarrier, N., Sommerfield, C., Pilgrim, H., & Humphreys, L. (1999). Cognitive therapy or imaginal exposure in the treatment of post-traumatic stress disorder: 12-month follow-up. British Journal of Psychiatry, 175, 571–575. [DOI] [PubMed] [Google Scholar]
  153. Taylor, S. (2003). Outcome predictors for three PTSD treatments: Exposure therapy, EMDR, and relaxation training. Journal of Cognitive Psychotherapy, 17(2), 149. [Google Scholar]
  154. Taylor, S., Thordarson, D. S., Maxfield, L., Fedoroff, I. C., Lovell, K., & Ogrodniczuk, J. (2003). Comparative efficacy, speed, and adverse effects of three PTSD treatments: Exposure therapy, EMDR, and relaxation training. Journal of Consulting and Clinical Psychology, 71, 330–338. [DOI] [PubMed] [Google Scholar]
  155. Ter Heide, F. J. J., Mooren, T., Kleijn, W., de Jongh, A., & Kleber, R. (2011). EMDR versus stabilisation in traumatised asylum seekers and refugees: Results of a pilot study. European Journal of Psychotraumatology, 2(1), 5881. [DOI] [PMC free article] [PubMed] [Google Scholar]
  156. Ter Heide, F. J. J., Mooren, T. M., & Kleber, R. J. (2016). Complex PTSD and phased treatment in refugees: A debate piece. European Journal of Psychotraumatology, 7(1), 28687. [DOI] [PMC free article] [PubMed] [Google Scholar]
  157. Thompson, S. G., & Higgins, J. P. (2002). How should meta‐regression analyses be undertaken and interpreted? Statistics in Medicine, 21(11), 1559–1573. [DOI] [PubMed] [Google Scholar]
  158. Tylee, D. S., Gray, R., Glatt, S. J., & Bourke, F. (2017). Evaluation of the reconsolidation of traumatic memories protocol for the treatment of PTSD: A randomized, wait-list-controlled trial. Journal of Military, Veteran and Family Health, 3(1), 21–33. [Google Scholar]
  159. van Minnen, A., Harned, M. S., Zoellner, L., & Mills, K. (2012). Examining potential contraindications for prolonged exposure therapy for PTSD. European Journal of Psychotraumatology, 3(1), 18805. [DOI] [PMC free article] [PubMed] [Google Scholar]
  160. Vaughan, K., Armstrong, M. S., Gold, R., O’Connor, N., Jenneke, W., & Tarrier, N. (1994). A trial of eye movement desensitization compared to image habituation training and applied muscle relaxation in post-traumatic stress disorder. Journal of Behavior Therapy and Experimental Psychiatry, 25, 283–291. [DOI] [PubMed] [Google Scholar]
  161. Wagenmans, A., Van Minnen, A., Sleijpen, M., & De Jongh, A. (2018). The impact of childhood sexual abuse on the outcome of intensive trauma-focused treatment for PTSD. European Journal of Psychotraumatology, 9(1), 1430962. [DOI] [PMC free article] [PubMed] [Google Scholar]
  162. Wells, A., & Sembi, S. (2012). Metacognitive therapy for PTSD: A preliminary investigation of a new brief treatment. Journal of Behavior Therapy and Experimental Psychiatry, 35(4), 307–318. [DOI] [PubMed] [Google Scholar]
  163. Wells, A., Walton, D., Lovell, K., & Proctor, D. (2015). Metacognitive therapy versus prolonged exposure in adults with chronic post-traumatic stress disorder: A parallel randomized controlled trial. Cognitive Therapy and Research, 39(1), 70–80. [Google Scholar]
  164. Yehuda, R., Pratchett, L. C., Elmes, M. W., Lehrner, A., Daskalakis, N. P., Koch, E., & Bierer, L. M. (2014). Glucocorticoid-related predictors and correlates of post-traumatic stress disorder treatment response in combat veterans. Interface Focus, 4(5), 20140048. [DOI] [PMC free article] [PubMed] [Google Scholar]
  165. Zandberg, L. J., Rosenfield, D., Alpert, E., McLean, C. P., Foa, E. B., Karatzias, T., … Adams, S. (2016). Predictors of dropout in concurrent treatment of posttraumatic stress disorder and alcohol dependence: Rate of improvement matters. Behaviour Research and Therapy, 80, 1–9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  166. Zang, Y., Hunt, N., & Cox, T. (2013). A randomised controlled pilot study: The effectiveness of narrative exposure therapy with adult survivors of the Sichuan earthquake. BMC Psychiatry, 13(1), 1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  167. Zang, Y., Hunt, N., & Cox, T. (2014). Adapting narrative exposure therapy for Chinese earthquake survivors: A pilot randomised controlled feasibility study. BMC Psychiatry, 14, 262. [DOI] [PMC free article] [PubMed] [Google Scholar]
  168. Zatzick, D. (2012). Toward the estimation of population impact in early posttraumatic stress disorder intervention trials. Depression and Anxiety, 29(2), 79–84. [DOI] [PubMed] [Google Scholar]
  169. Zlotnick, C., Shea, T. M., Rosen, K., Simpson, E., Mulrenin, K., Begin, A., & Pearlstein, T. (1997). An affect‐management group for women with posttraumatic stress disorder and histories of childhood sexual abuse. Journal of Traumatic Stress, 10(3), 425–436. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Citations

  1. Higgins, J., & Green, S. (2011). Cochrane handbook for systematic reviews of interventions. The Cochrane Collaboration. Retrieved from www.cochrane-handbook.org
  2. International Society of Traumatic Stress Studies (ISTSS) . (2018). New ISTSS Prevention and Treatment Guidelines [Online]. Retrieved from http://www.istss.org/treating-trauma/new-istss-guidelines.aspx

Articles from European Journal of Psychotraumatology are provided here courtesy of Taylor & Francis

RESOURCES