Veterans regaining control; preliminary effects of inpatient Dialectical Behavior Therapy based PTSD treatment

ABSTRACT

Introduction: Trauma-focused therapy (TFT) is highly effective in posttraumatic stress disorder (PTSD). However, there is some evidence that TFT is less effective in specific groups, such as veterans and people with comorbid personality disorders, emotion regulation problems or substance use disorders.

Aim: In this pre–post pilot study, we investigated feasibility and effectiveness of a 12-week veteran intensive treatment consisting of integrated Dialectical Behavior Therapy (DBT) and TFT, in Dutch veterans with PTSD, comorbid emotion regulation and/or substance use problems.

Results: Self-reported PTSD symptoms (PCL-5) showed a statistically significant decrease from pre- to posttreatment, with a large effect size (Cohen’s d = 2.92), as well as general psychiatric symptoms (OQ-45, Cohen’s d = 1.85). Self-efficacy (Dutch SES) significantly increased with a medium effect size (Cohen’s d = 0.80). Reduction of total score of borderline personality symptoms (PAI-BOR) did not reach statistical significance, although its subscale affective instability showed a statistically significant medium decrease (Cohen’s d = 0.59). Feasibility of implementation of the treatment programme was sufficiently good, with a response rate on posttreatment measurements of 66% and 50% at 6 and 10 weeks respectively. Patients who did not completed the posttreatment measurements did not significantly differ on primary and secondary outcome measures from completers.

Conclusion: Feasibility and preliminary results from the 12-week DBT-based veteran intensive treatment programme are positive. This provides hope and opportunity for this patient group with a generally less positive response to regular evidence-based PTSD treatments.

HIGHLIGHTS

• In this pre–post pilot study, we investigated feasibility and effectiveness of a newly developed 12-week intensive treatment for Military Veterans with Posttraumatic Stress Disorder (PTSD), who did not benefit from regular treatment.

• The inpatient treatment programme consists of a combination of Dialectical Behavior Therapy (DBT) and Trauma-focused Therapy and is one of its kind in current Veteran mental health services.

• Preliminary results from this veteran intensive treatment programme are positive. This provides hope and opportunity for this patient group with a generally less positive response (compared with civilians) to regular evidence-based treatments for PTSD.

1. Introduction

Although most post-active veterans label their mission periods as purposeful, at least 10% (i.e. more than 10,000 veterans in the Netherlands) experience mission related psychiatric symptoms. Only around 25% reaches out for help from specialized veteran social and mental health care (Nederlands Veteraneninstituut, 2023). Posttraumatic stress disorder (PTSD) is one of the most frequently diagnosed disorders following military trauma exposure (Seal et al., 2007; Vasterling et al., 2010). After exposure to a traumatic event, the average risk for developing PTSD is 5–10%, but specific trauma types, such as being held captive, being kidnapped, tortured or raped, are associated with higher risk of PTSD, up to 49% (Kessler et al., 2017; Liu et al., 2017). PTSD has an estimated lifetime prevalence of 5.6–8.3% (Kilpatrick et al., 2013; Koenen et al., 2017). The clinical and societal burden of PTSD is high, in terms of unemployment and health costs (Fischer et al., 2023; Gradus, 2017).

Trauma-focused therapies (TFT), such as Imaginary Exposure (IE), Eye Movement Desensitization and Reprocessing (EMDR) and cognitive therapy, show high effect sizes in treating PTSD (Cusack et al., 2016; Karatzias et al., 2019; Lewis et al., 2020). However, response rates vary around 56–67% (Bradley et al., 2005; Dorrepaal et al., 2014), dropout from treatment is high (36–54%; Imel et al., 2013; Najavits, 2015), and PTSD symptom course varies considerably over time (Vasterling et al., 2023). Specifically, TFT seems to be less effective in veterans (Haagen et al., 2015). One possible explanation is the high comorbidity with personality problems and substance use disorders. Comorbidity of personality disorders in PTSD is substantial in general (22–26%; Friborg et al., 2013) and even higher in veterans (45%; Dunn et al., 2004). This is associated with more severe PTSD symptoms, emotion regulation problems and poorer functioning (Frías & Palma, 2015). Another possible explanation for the reduced effectiveness of treatment for veterans, is the difficulty they have in opening up to a ‘civilian psychologist’. The military world, with its rules and predictability, often clashes with that of civilian society. Veterans find that upon returning to civilian life, they still navigate life as if they are on deployment. They are more alert, feel unsafe more quickly in crowds or in disorganized places, have a strong sense of justice, and a need for clarity. This often conflicts with the more ambiguous civilian society where different norms and values exist. This ambiguity makes veterans distrustful and leads them to have difficulty in trusting people, including the therapist. When treating veterans, it is important that the therapist has sufficient contextual knowledge so that they can connect well with the veteran's experiential world.

Recent studies build on the evidence base that trauma-focused treatments can be safely and effectively applied in adults with PTSD and comorbid personality disorders. Still, quite some non-response exists in people with PTSD and personality disorders, justifying the need for research whether non-responders would still improve from a combination treatment (TFT plus a treatment aimed at personality problems) (Markovitz et al., 2015; Slotema et al., 2020; Snoek et al., 2021; End van den et al., 2024). On the other hand, as said, TFT shows considerable dropout and to increase attendance for specific group therapies, TFT has been successfully combined with dialectical behavior therapy (DBT), an evidence-based treatment for borderline personality disorder (Stoffers et al., 2012) in mostly female patients (80%) with comorbid borderline personality disorder, with a variable treatment duration (on average 17.2 months), offering only Prolonged Exposure as TFT (Harned et al., 2021). Also in female patients with a history of childhood sexual and/or physical abuse (Bohus & Priebe, 2018). In the case of veterans there is evidence for the effectiveness of TFT-DBT in female veterans with PTSD primarily related to childhood (sexual trauma) and emotion regulation problems (Goodman et al., 2016; Koons et al., 2001) as well as a 12-week outpatient TFT-DBT programme with promising results for both male and female veterans, but with a high drop-out rate of 33.3% (Meyers et al., 2017).

One problem contributing to the inability to successfully complete trauma treatment may be an inability to allow emotions to surface, which is necessary for trauma-focused treatment to be effective. Veterans are trained to shut down emotions to be effective as soldiers in combat. As a consequence, they often have limited emotion-based knowledge, a degree of affect-phobia and limited emotion regulation skills. Mindfulness training, which is DBT's core business, entails a way of tuning into their feelings, without judgement, enabling the trauma-focused work to be done. In addition, the emotion regulation module in DBT skills training helps to develop the ability to recognize, identify and regulate emotions.

More specifically DBT is based on a world view in which reality consists of continuing opposing forces. The therapist's dialectical strategies reflect these opposing forces by constantly moving between acceptance (e.g. validation, reciprocity) and motivation to change (e.g. irreverence, problem solving). DBT consists of (1) individual therapy, (2) skills training with 2 modules focused on acceptance: mindfulness and frustration tolerance; and 2 modules focused on change: emotion regulation and interpersonal skills, (3) (telephone) consultation between sessions, and (4) a consultation team for therapists (Linehan, 2015). Goals of DBT are increasing motivation (commitment, in both clients and therapists), learning skills and generalizing skills to the client's environment. Research into the effectiveness of the treatment indicates that DBT helps to increase commitment to therapy (Steuwe et al., 2017) and self-efficacy, but not yet in veterans (Dijk van et al., 2013). The aim of the present study is to investigate feasibility and effect of an intensive 12-week in-patient treatment programme including a combination of DBT and twice-weekly TFT. The research questions are:

1. is the combined DBT-TFT treatment programme in veterans with PTSD plus comorbid emotion regulation problems and/or substance use feasible?

2. Is the combined DBT-TFT treatment programme effective in decreasing a. general psychiatric symptoms, b. PTSD symptoms, c. borderline personality problems, and d. increasing experienced self-efficacy.

2. Method

2.1. Design and participants

The present study is an open, naturalistic pre–post pilot study among adult (18–65 years) clients who were admitted to the inpatient treatment programme, after failing outpatient treatment, between 1st September 2021 and 1st September 2022. The client sample consists of 31 participants, all of whom are men and all of whom have received earlier treatment(s) which have been unsuccessful.

Inclusion criteria were a diagnosis of PTSD according to the criteria of DSM-5 (American Psychiatric Association, 2014), as measured by the Clinician Administered PTSD Scale (CAPS-5; Weathers et al., 2013; Boeschoten et al., 2014), with emotion or aggression regulation problems (as measured by the PAIBOR, Personality Assessment Inventory-Borderline, Distel et al., 2009) and/or a substance use disorder (in case of severe SUD according to DSM-5 criteria, 7–10 days of detoxification in an addiction clinic was being added prior to the intervention). Exclusion criteria were clinical diagnoses of psychotic or bipolar disorder; intellectual disability was not. Measuring exclusion criteria was done by following a pre-structured intake format checking DSM-5 criteria by a trained psychologist, and in case of possible intellectual disability an IQ test was being performed. The final sample included one client with an IQ below 80, who dropped out.

Therapists informed the patients about the study with assurance that refusal would not affect treatment, after which a research assistant contacted the patient. All interviews were performed by trained doctoral level psychologists working under supervision. Written informed consent (IC) was obtained in person after screening for eligibility in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki). Patients received detailed information about psychological treatment in the context of scientific research as part of the informed consent procedure. Due to the design of the study, the research assistant was not blind to the intervention. In the case of treatment dropout, data collection was continued if possible. Data was stored on a secure server. Data collection, storage and sharing was done in accordance with the Dutch General Data Protection Regulation.

2.2. Intervention

The inpatient 12-week treatment programme integrates TFT with DBT. It consists of an open setting with, on average, one discharge and one admission per week. Figure 1 provides a visual representation of the treatment programme.

Figure 1.

Schedule of the 12-week veteran intensive inpatient treatment.

In comparison to outpatient DBT programmes for BPD, the pre-treatment phase of DBT was rather limited in this study, because the treatment was primarily focused on PTSD in which precommitment phase is not common. Nevertheless, we extended the intake phase with a precommitment session to assess practical barriers, personal strengths, and pitfalls of the client in being able to handle the intensity of the treatment programme, his/her need for validation and capacity to handle the confrontational style of DBT. During these sessions the DBT commitment strategies were used, thus strengthening client’s motivation for the treatment. TFT consists of 24 twice-weekly 75–90 min sessions of Imaginary Exposure (IE), Eye Movement Desensitization Processing (EMDR), Imagery Rescripting (ImRs) or a combination of these. In a shared decision-making process client and therapist chose the type of evidence-based trauma-focused treatment from three techniques on offer: Imaginary Exposure, EMDR, Imagination and Re-Scripting Therapy. Factors included in the decision-making process were prior treatments (switch technique if former technique wasn't effective), type of trauma (considering ImRs if also early trauma), and risk of cognitive or affective avoidance with EMDR. The first 2–4 sessions are used to map out a timeline with formative positive and negative life events from birth to the present, distinguishing between adverse life events and PTSD-criterion-A traumatic events, the latter becoming targets for active trauma processing. In addition, avoidant and safety behaviour is charted, and an exposure-in-vivo plan created.

Clients attend DBT skills training twice weekly, consisting of a total of 24 90-minute group sessions during which the four DBT modules are offered, with a selection of skills based on Training schedule 7 (Linehan, 2015, adapted from table 4.5 in Swenson et al., 2007). Each client receives weekly individual DBT sessions, using the DBT diary card and chain analyses. DBT coaching is offered 24/7 by in-patient staff. All staff have been both formally and informally trained in DBT, including a period of external supervision from the Dutch DBT expertise centre ‘Dialexis’. All staff attend weekly Consultation Team meetings. In addition to this, clients receive pharmacotherapy (with a focus on tapering off sedative medication, such as benzodiazepines and antipsychotics), CBT interventions for insomnia and substance use, daily sport activities, psychomotor and creative therapy, and psychoeducation. The programme also incorporates 3 joint 60–90-minute sessions with (a) significant other, focused on how to meet practical and emotional needs of both client and significant others during and after the treatment the programme. A safety/skills plan is made during the programme by the client and staff, in which the significant other is asked to participate. In addition, one 120-minute family/friends – session is organized in which client is assisted in providing psychoeducation on the PTSD/DBT programme. This session is supported by 2 staff members.

2.3. Measurements

Measurements were conducted at baseline (T0); mid- (T1), and post-treatment (T2). Baseline measurement consisted of clinical interviews and self-report questionnaires; at all other timepoints exclusively of self-report questionnaires. Figure 2 visually illustrates the design, time points and measurement during the intervention.

Figure 2.

The Design, Time Points and Measurements during the Intervention.

2.4. Baseline measurements

• – LEC-5 (Life Events Questionnaire, Weathers et al., 2013) is a self-report questionnaire measuring 17 adverse or traumatic life events.

• – CAPS-5 (Clinician Administered PTSD Scale, Boeschoten et al., 2014; Weathers et al., 2013) is the gold standard clinical interview to determine presence of DSM-5 PTSD. Severity of PTSD is measured with a 4-point scale on the 20 DSM-5 PTSD symptoms (range total score 0–80). The CAPS has shown good reliability and a good con- and divergent validity (Weathers et al., 2018).

• – SCID-5-S (Structured Clinical Interview for DSM-5 Syndrome Disorders – Dutch version) is a semi-structured interview to measure presence and severity of DSM-5 syndrome disorders (APA, 2017; First et al., 2015). The SCID-5-S shows acceptable to excellent internal consistency and reasonable test-retest reliability (Shankman et al., 2018).

• – SCID-5-P (Structured Clinical Interview for DSM-5 Personality Disorders – Dutch version, First et al., 2016) is a semi-structured interview for DSM-5 personality disorders, preceded by a 106-item self-report screener. The predecessor of the SCID-5-P (i.e. SCID-II) showed excellent inter-rater reliability, moderate to good test-retest reliability and sufficient internal consistency (Lobbestael et al., 2011; Maffei et al., 1997; Weertman et al., 2003).

2.5. Primary outcome

• – PCL-5 (PTSD Checklist, Weathers et al., 2013) is a 20-item self-report questionnaire measuring PTSD severity according to DSM-5 PTSD B, C, D, E-criteria, on a Likert scale from 0 to 4 (range 0–80). PCL-5 scores higher than 31–33 are indicative of probable PTSD across samples (Weathers et al., 2013).

2.6. Secondary outcomes

• – OQ-45 (Outcome Questionnaire, Jong de et al., 2008) measures the progress of adults who receive treatment for mental illness. It contains three dimensions: (1) Symptomatic distress/psychological functioning (25 items), (2) (Dis)functioning in interpersonal relations (11 items), and (3) (Dis)functioning in social roles (9 items), rated on a Likert 5-point scale from 0 (never) to 4 (almost always) (total score range 0–180). Dutch normative data show a mean total score in healthy persons of 38.7 (SD = 16).

• – PAI-BOR is a 24-item self-report questionnaire for measuring severity of borderline personality symptoms, consisting of four domains: Affective Instability (AI), Identity problems (IP), Negative Relations (NR) and Self-destructive behaviour (SB). All items are rated on a 4-point scale from 0 (completely untrue) to 3 (completely true) (total score range from 0 to 72; 38 or higher indicating clinically relevant symptoms). Mean total score in the Dutch population is 15.4 (SD = 8); with mean domain scores Affective Instability = 4.4 (SD = 3), Identity problems = 3.9 (SD = 2.7), Negative relations = 4.5 (2.7) and Self-destructive behaviour = 2.7 (SD = 2.3).

• – SES (Self-Efficacy Scale, Schwarzer & Jerusalem, 1995) is a uni-dimensional questionnaire that measures how the person generally copes with stressors/ adversities in life. It contains 10 phrases describing how a person thinks and behaves in general. In contrast to measuring optimism, it focuses explicitly on self-reliance, that is the belief his/her actions are responsible for successful outcomes. The items are rated on a 4-point Likert scale from 1 (completely false) to 4 (completely true) (range of 10–40). No cut-off score has been defined, but higher scores indicate a higher level of Self-Efficacy, with a mean score in diverse populations of 29 (Schwarzer & Jerusalem, 1995).

2.7. Further outcome measures:

• – CQI (Consumer Quality Index, Stichting Benchmark GGZ, 2016) is a 21-item self-report questionnaire for measuring quality aspects of Mental Health Care and Addiction Care, consisting of six domains: Therapeutic relationship, Accessibility of the therapists, Shared decision making, Treatment implementation, Sense of safety and Accommodation and hospital environment, rated on a 5-point scale from 1 (no, not at all) to 5 (yes, completely), with higher scores indicating more contentment with the treatment.

• – Qualitative outcome data: Evaluation by clients recorded during exit interview: How helpful was the treatment on a scale of 0–10 in achieving their own specific treatment goals? In your opinion, what were the most effective parts of the treatment?

2.8. Statistical procedure

Statistical analyses were done using the SPSS statistics programme (Version 28. IBM corp, 2021). Baseline group variables were described with means/standard deviation (SD) for continuous variables and numbers/percentages for dichotomous variables. For the baseline continuous variables, an independent t-test was used to examine whether dropouts differed from completers. Differences between pre-, mid- and post-measurements of the primary outcome measure PCL-5, and the secondary outcome measures OQ-45, PAI-BOR and Dutch SES were analysed with a repeated measures ANOVA over the three timepoints (T0, T1 and T2), using the Bonferroni option, in SPSS, after checking the following assumptions: absence of outliers, normal distribution, homogeneity variance and sphericity.

The Cohen’s D effect size (mean pre – mean post/SD pre) was calculated as a measure of effect size. This interpretation of effect sizes is $\ge$.30 = small effect size; $\ge$.50 = medium effect size; $\ge$.80 = large effect.

This study being a pilot with a relatively small sample size caused us to refrain from a missing data handling procedure. Therefore, we tested with an independent T-test if non-completers (n=16 at T2) differed from completers (n=15), and it appeared that there was no statistical difference on demographic variables (all male; age, education both p > .05), on primary and on secondary outcome measures (PCL-5, resp. OQ-45, PAI-BOR, SES; all p > .05). Thus, those factors were not candidate for selection bias.

3. Results

3.1. Sample selection and description

Of 39 clients admitted to the inpatient treatment programme, seven were excluded because it was a re-admission. In addition, one client refused to participate in the study, resulting in 31 participating clients (described in Table 1). Of these, 3 prematurely discontinued their treatment (drop-out) and 1 client was unable to complete the questionnaires, resulting in a final research sample of 27 completers. The final sample consisted mainly of working adult men with an intermediate vocational education level, with mean 1.8 missions, mostly to Afghanistan and Bosnia. Most respondents had been previously treated for PTSD in an outpatient and/or in an intensive inpatient treatment programme. Nevertheless, the respondents met full PTSD-criteria (CAPS-5). Most prevalent comorbidities were depressive, alcohol and substance use, and anxiety disorders. One quarter of participants fulfilled criteria for a personality disorder (obsessive-compulsive, borderline, or avoidant personality disorder). PTSD-severity was high. General psychiatric symptoms were moderately high. Borderline symptoms approached the cut-off for clinical significance (>38).

Table 1.

Description of the included adult veterans (N = 31).

Demographics
Sex (% men)		100%
Age in years (mean, SD)		42.6 (7.7)
Educational level (%)	Vocational level College Education	94% 6%
Army unit (%)	Ground Forces Air Forces Navy	87% 10% 3%
Missions (mean number/SD pp)		1.8 (1.4)
	Afghanistan (total number)	26
	Bosnia (total number)	15
	Other (total number)	15
Marital status	Married or partnered (%) Single (%)	71% 29%
Number of children (mean/SD)		1.6 (1.3)
CAPS PTSD-classification (%)		100% (n = 31)
PCL-5 PTSD-severity total (mean/SD)	n = 29	54.6 (11.4)
– PCL-5-criterium B		13.1 (3.4)
– PCL-5-criterium C		5.7 (1.8)
– PCL-5-criterium D		19.1 (4.6)
– PCL-5-criterium E		16.7 (3.5)
SCID-5-S No. actual diagnoses (mean/SD)	n = 25	1.2 (1.4)
Most prevalent comorbid syndrome disorders	8 Depressive, 9 alcohol use, 8 drug use, 6 anxiety disorder
SCID-5-P No. diagnoses (mean/SD)	n = 27	0.5 (0.7)
Personality disorder type	4 obsessive, 2 avoidant, 1 borderline personality disorder
General psychiatric symptoms (OQ-45.2)	n = 29	97.0 (14.1)
– OQ: Symptomatic distress		56.8 (11.4)
– OQ: Interpersonal relations		23.6 (4.2)
– OQ: Social role		16.5 (4.7)
Borderline personality symptoms (PAI-BOR)	n = 29	33.3 (9.1)
– PAI-BOR: Affective instability		8.9 (3.7)
– PAI-BOR: Identity problems		8.6 (3.7)
– PAI-BOR: Negative relations		7.5 (2.4)
– PAI-BOR: Self-destructive behaviour		8.4 (1.9)
Sense of Self-efficacy (Dutch SES)	n = 29	27.5 (4.9)

*Statistically significant difference p < .05; ns = not statistically significant.

CAPS: Clinician Administered PTSD Scale; Dutch SES: Dutch Self-Efficacy Scale; OQ-45.2: Outcome Questionnaire; PAI-BOR: Borderline personality symptoms; PCL-5: PTSD Checklist; SCID-5-S: Structured Clinical Interview of DSM-5 Syndrome Disorders; SCID-5-P: Structured Clinical Interview of DSM-5 Personality Disorders.

3.2. Feasibility

The implementation of the intervention was deemed to be feasible. (Clinical) Psychologists were trained in both EMDR and IE, and they attended monthly supervision. Six of nine practitioners were formally trained in DBT by the Dutch DBT expertise centre Dialexis (10-day DBT-training), the rest of the team attended in-house DBT-training by an experienced DBT-therapist The entire team attended weekly meetings of the DBT consultation team and external supervision through Dialexis.

Conducting a pilot study in a naturalistic setting provided the opportunity to extend the diagnostic process, especially for syndrome and personality disorders using clinical semi-structured interviews. There was a large response to the interviews upon admission: 29 out of 31 clients completed the CAPS, 25 the SCID-5-S and 27 the SCID-5-P (mean response 87%) and self-report questionnaires were almost 100% completed upon admission. Response to posttreatment questionnaires was lower: 66% after 6 weeks and 50% after 12 weeks.

While almost all clients were willing to cooperate and recognized the usefulness of this study, there were several reasons for non-completion. Clients regularly reported that they found the questionnaires too long to complete in addition to participating in the already intensive treatment programme.

3.3. Quality of care

Results from CQI and the exit interview indicated that clients generally experienced the treatment as very positive, giving an average grade of 8.75 out of 10. A total of 16 clients completed the CQI during the research period. Looking at the different domains, ‘Treatment relationship’ showed an average score of 4.7 (SD 0.4) out of 5; ‘Accessibility of the therapist’ showed an average score of 4.5 (SD 0.5); ‘Shared decision making’ an average score of 4.0 (SD 0.9); ‘Implementation of treatment’ an average score of 4.2 (SD 0.5); ‘Sense of safety’ an average score of 4.5 (SD 0.6); ‘Accommodation and Hospital environment’ an average score of 4.4 (SD 0.6). The exit interviews indicated that most of the clients experienced a decrease in PTSD symptoms and associated avoidance behaviour. They indicated that the use of DBT skills had led to better emotion regulation, a decrease in stress levels and more connection with their environment. Clients reported that they were once again able to undertake pleasurable activities and enjoy them. More than half of the clients indicated during the exit interviews that they experienced future prospects again. Two clients explicitly indicated that they had noticed a decrease in suicidality. TFT, exposure-in-vivo and DBT skills training were mentioned as the most effective components. Feedback on the programme was that more attention should be paid to the transition to home, both during and after treatment.

3.4. Treatment outcome

Table 2 shows that mean PTSD symptoms (PCL-5) statistically significantly decreased, with a large effect size to below the cut-off for PTSD. General psychiatric symptoms (OQ-45.2) showed a statistically significant decrease with a large effect size. The largest gains were found between 6 and 10 weeks.

Table 2.

Baseline, mid- and posttreatment measurements.

	Baseline (mean/SD)	6 weeks (mean/SD)	10 weeks (mean/SD)	F	p	Cohen’s d 0–6 weeks	Cohen’s d 6–10 weeks	Cohen’s d 0–10 weeks
PCL-5 total score	54.6 (11.4) n = 29	42.0 (15.0) n = 21	21.3 (15.0) n = 15	46.1	<.001*	1.11	1.82	2.92
B: Intrusions	13.1 (3.4)	10.5 (4.9)	5.4 (4.7)	21.8	<.001*
C: Avoidance	5.7 (1.8)	3.5 (1.8)	1.5 (1.8)	31.6	<.001*
D: Negative mood & cognitions	19.1 (4.6)	15.0 (5.6)	7.5 (5.1)	47.7	<.001*
E: Hyperarousal	16.7 (3.5)	13.0 (4.4)	6.9 (4.4)	36.5	<.001*
OQ-45.2 total score	97.0 (14.1) n = 29	89.5 (15.9) n = 21	70.9 (16.5) n = 15	25.1	<.001*	0.53	1.32	1.85
OQ: Symptomatic distress	56.8 (11.4)	51.8 (12.5)	36.4 (12.1)	29.9	<.001*
OQ: Interpersonal relations	27.6 (4.2)	22.7 (3.2)	21.2 (3.7)	2.3	<.123
OQ: Social role	16.5 (4.7)	15.1 (5.0)	13.3 (3.7)	12.8	<.001*
PAI-BOR total score	33.3 (9.0) n = 29	31.0 (8.3) n = 21	28.0 (10.7) n = 15	2.4	.105ns	0.26	0.33	0.59
Affective instability	8.9 (3.1)	7.1 (4.1)	5.5 (4.0)	7.0	.003*
Identity problems	8.6 (3.7)	7.6 (2.4)	6.7 (3.5)	1.5	.24 ns
Negative relations	7.5 (2.4)	7.8 (2.5)	7.1 (2.2)	0.2	.84 ns
Self-destructive behaviour	8.4 (1.9)	7.7 (2.7)	8.7 (2.6)	2.2	.13 ns
Dutch SES total score	27.5 (4.9) n = 29	28.2 (4.6) n = 21	31.4 (4.5) n = 15	15.2	<.001*	0.14	0.65	0.80

*Statistically significant difference (Bonferroni corrected) *p < .001; ns = not statistically significant.

Cohen’s d > .20 = small effect size; > .50 = medium effect size; > 0.8 = large effect size.

Mean total borderline personality symptoms (PAI-BOR) decreased as well, and although this was not a statistically significant effect, it was clinically relevant with a medium effect size; one of its subscales ‘affective instability’ showed a statistically significant effect on the final measurements. Sense of self-efficacy (Dutch SES) increased with a statistically significant effect and a medium–large effect size. As mentioned earlier, non-completers on posttreatment measurements (n = 14) did not differ significantly from completers (n = 15) on demographic variables, primary and secondary outcome measures.

4. Conclusion and discussion

In veterans with PTSD and comorbid emotion regulation and/or substance use disorders, a novel 12-week veteran inpatient treatment programme, based on TFT in combination with DBT, resulted in statistically significant decreases in PTSD symptoms, as well as in general psychiatric symptoms, with large effect sizes, whereby the largest gains were found between 6 and 10 weeks. In addition, sense of self-efficacy increased significantly, with a medium to large effect size. Although improvement in overall borderline symptoms was not statistically significant, the subscale affective instability decreased statistically significantly, with a medium effect size. These results indicate that by the end of treatment, clients suffered significantly less from both general psychiatric symptoms and specific PTSD symptoms. Regarding the last, the results indicate that the average posttreatment score decreased to below the clinical cutoff score for PTSD. This is remarkable since this population experienced little or no benefit from previous TFTs.

This study aligns with a previous study that examined outpatient DBT-PTSD treatment for veterans (Meyers et al., 2017), with the added benefit of a low drop-out rate (less than 10%) in an inpatient setting, compared to the 33,3% drop-out rate in the outpatient programme investigated by Meyers et al. (2017).

Other studies investigating the effectiveness of combined PTSD and DBT interventions, have primarily focused on female participants with Childhood Sexual Abuse (CSA) as the main trauma (Prillinger et al., 2024). Different from these studies, the population researched in this study consists of mostly male veterans, all of whom have primarily experienced traumatic events during one or more military missions, some of whom have in addition experienced traumatic events during childhood, before and or after their missions. Additionally, previous research on combined treatments has only used PE or DBT-PTSD treatment, whereas the current study has examined the effectiveness of other forms of trauma-focused therapy (TFT), such as EMDR and IE, which have proven to be effective. In addition, the treatment programme differs from previous studies in the particular combination of length (12 weeks), setting (inpatient) and structure (concurrent DBT plus TFT throughout the 12 weeks).

4.1. Possible explanations for findings

While, similarly to other studies (Meyers et al., 2017; Harned et al., 2021; Bohus et al., 2013), it is not possible to conclude which ingredients of the treatment programme are responsible for the positive treatment outcome as described above, it is worthwhile to consider possible explanations for the results on each of the outcome variables. These considerations may contribute to formulating future research questions. We will therefore propose a number of hypotheses in relation to each of the outcome variables.

4.2. PTSD symptoms

A plausible assumption is that providing a higher ‘dose’ of TFT (twice weekly and simultaneous daily in-vivo exposure) is most likely the primary active ingredient. A more intensive trauma treatment may lead to faster symptom reduction, which contributes to the motivation to continue treatment (Oprel et al., 2021). In addition, the idea behind the integrated DBT-TFT programme is that the DBT skills and overall DBT approach also make clients more motivated to complete therapy, as well as adept at tolerating intense emotions and thus completing TFT. Additional factors, such as abstinence from substances, the predictable day structure, the ever-present support and coaching by the DBT-trained 24-hour (nursing)staff, the use of a crisis plan, sports, Finally, in an inpatient setting, there is less opportunity for clients to engage in avoidant behaviour.

4.3. Borderline symptoms

However, PTSD symptoms improved more significantly than the borderline symptoms targeted by DBT. An explanation for this may be that although borderline symptoms in hospitalized veterans are almost twice as common compared to the general Dutch population, the severity, as measured at intake, was below the cut-off point for clinical significance (.38), leaving less room for improvement. Another explanation for the smaller reduction in borderline symptoms may be that the duration of the 12-week inpatient skills training may not be sufficient to generalize the skills to the home situation.

4.4. Self-efficacy and general psychiatric symptoms

Experiencing a significant decrease in general psychiatric and PTSD symptoms may be the most logic explanatory factor for the increased sense of self-efficacy, Alfonsson et al. (2022) found a correlation between improved self-efficacy and reduced general psychiatric symptoms in clinical oupatients with emotion regulation difficulties. In addition, it is theoretically expected that increased DBT skills and a more effective balance between change and acceptance should also lead to an increased sense of self-efficacy. For instance, Van Dijk et al. (2013) showed that DBT skills help increase self-efficacy in patients with bipolar disorder. Barnicot et al. (2016) found that self efficacy improves with DBT skills and correlates with better treatment retention and less self harm in patients with borderline personality disorder.

4.5. Limitations of this study

This study suffers from several methodological limitations. Firstly, in relation to the research sample. The sample size is small and suffers from possible selection bias by not having randomization and control participants, and the exclusive reliance on self-report outcome measures. Although the clients who responded to the questionnaires did not differ significantly from the clients who did not respond, given the lower follow-up response rate and the lack of a control group, the results of this study should be viewed with caution. In addition, this study exclusively consists of male respondents (due to mostly male clients being referred to our clinic), therefore these results cannot be generalized to a female veteran population. Clients with a below-average IQ experienced problems with completing the measurement instruments (in terms of the quantity and the complexity and language of these instruments). In addition, they indicated that they had trouble with the level of the group interventions, the DBT skills training written material, as well as the homework assignments. This makes our programme less effective for this target group. In addition, this pilot study cannot shed light on which specific components of the veteran intensive treatment programme were responsible for reducing general psychiatric and PTSD symptoms.

4.6. Recommendations

This treatment programme provides an essential service for veterans in the Netherlands that was missing until recently, which has now been tested for feasibility and initial effectiveness. It also provides new knowledge about how to measure sense of self-efficacy in veterans and whether this can be improved by treatment. Given the positive initial results found through this pilot study, we recommend setting up a randomized controlled trial (RCT) to plot the effects against a control group, ideally including a sufficient number of female veterans. Such research may further contribute to the success/effectiveness of treatment by increasing competence, empowerment, and motivation for change. A second recommendation relates to follow-up treatment. Because standard DBT treatment consists of a second refresher cycle of skills training, aimed at implementing and generalizing new skills, it is important to make DBT available in outpatient programmes for veterans, including as a form of outpatient follow-up treatment after completion of the 12-week inpatient programme as described above. In this way relapse rates might be reduced in this target group.

In conclusion, the present pilot study shows preliminary positive effects of an intensive, inpatient 12-week programme, integrating DBT and TFT on (1) PTSD symptoms, (2) general psychiatric symptoms, (3) perceived self-efficacy and on (4) affective instability in male veterans with PTSD, emotion regulation problems and substance use disorders who have previously undergone outpatient and/or inpatient PTSD treatment without satisfactory results. The study supports the continuation of the treatment programme and it provides direction for the improvement of the follow-up treatment upon completion of this programme. The study also provides suggestions in relation to the design of future studies and may assist in formulating further research questions, particularly in relation to understanding active ingredients of such a programme.

Funding Statement

This work was funded by a Research and Development Grant LZV (‘Landelijk Zorgsysteem voor Veteranen’) awarded by the Dutch Ministery of Defense and the Sinai centrum, Amstelveen.

Author contributions statement

Gerda Wesseling: Design, Literature/Text; Evelyn Nispeling: Data collection, Analyses; Juernene Tholel: Data Collection; Shanna Teunissen: Literature/Text; Kathleen Thomaes: Primary design, Analyses, Literature/Text.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The participants of this study did not give written consent for their data to be shared publicly, therefore the data-set supporting this research cannot be made available.

Ethics statement

Written informed consent was obtained in person after screening for eligibility in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki)