Feigenbaum 2012.

Study characteristics
Methods	Design: randomised control trial
Participants	Participants: referrals to a new specialist personality disorder service Sex: (for sample as a wholea) female (n = 30/41, 73%); male (n = 11/41, 27%) Age: (for sample as a wholea). Intervention group, dialectical behaviour therapy (DBT): mean 35.4 years (SD = 7.8, range = 23 ‐ 56 years) Control group, treatment‐as‐usual (TAU): mean = 34.6 years (SD = 7.4, range = 23 ‐ 45 years) Unit of Allocation: cluster (balancing for geographic, demographic (gender) and diagnostic criteria (presence of borderline personality disorder)); for every 3 patients randomised, 2 assigned to DBT and 1 to TAU Number randomised: 41 (for sample as a wholea). DBT group n = 25; TAU group n = 16 Number completing: 31 (for sample as a wholea). DBT group n = 17; TAU group n = 14 Setting: National Health Service (NHS) specialist personality disorder service; London, UK Inclusion criteria: diagnosis of cluster B personality disorder; aged 18‐65 years old; provide written consent Exclusion criteria: currently in long‐term psychotherapeutic treatment; meet DSM‐IV criteria for comorbid psychotic disorder or bipolar disorder; opiate dependence requiring specialist treatment; mental impairment; evidence of organic brain disorder Ethnicity: not stated Baseline characteristics (for sample as a wholea) Relationship status: single (83%); currently married (5%); co‐habiting (2%); separated/divorced (10%) Education status: comprehensive education (15%); no formal education (37%); A‐level (15%); first degree (7%); second degree (2%); vocational training (22%) Years of education; DBT group mean = 12.38 (SD = 1.8, range = 8‐17 years); TAU group mean = 13.4 (SD = 2.5, range = 10‐18 years) Employment status: unemployed (90%); full‐time or part‐time paid work (5%); homemaker (5%) Substance use: alcohol as comorbid misuse substance (27%); illicit drugs as comorbid misuse substance (20%) Cluster A personality disorder diagnosis: DBT group (10/25, 40% paranoid PD); TAU group (3/16, 19% had paranoid, schizotypal or schizoid PD) Cluster B personality disorder diagnosis:b DBT group 23/25 (92%) borderline PD, 7/25 (28%) antisocial PD, 1/25 (4%) narcissistic PD; TAU group 15/16 (94%) borderline PD, 4/16 (25%) antisocial PD, 2/16 (13%) narcissistic PD Cluster C personality disorder diagnosis: DBT group 9/25 (36%) avoidant PD, 2/25 (8%) dependent PD, 1/25 (4%) obsessive compulsive PD; TAU group 6/16 (38%) avoidant PD
Interventions	Two conditions: dialectical behaviour therapy (DBT); or treatment‐as‐usual (TAU) (2:1 allocation) Experimental group: DBT (n = 25 randomised) Control group: TAU (n = 16 randomised) Details of conditions: Intervention group: DBT pretreatment phase of 3‐6 weeks of goal‐setting and commitment‐building followed by offer of 1 year DBT treatment contract; DBT treatment consists of 1 hour of individual therapy and 2.5 hours of group skills training per week plus out‐of‐hours telephone consultation as required Control group: TAU consists of a range of individualised service provision including outpatient psychiatric review, case management, psychoanalytic psychotherapy, cognitive behaviour therapy, supportive structured counselling, inpatient admission, drug and alcohol treatment and crisis management. TAU provision for personality disorder within the region may include schema therapy. Duration of intervention: 55‐58 weeks Duration of trial: 20 months Length of follow‐up: 12 months after baseline
Outcomes	Primary outcomes Aggression: Overt Aggression Scale (OAS) Adverse events: Self‐harm and suicide attempts from semi‐structured interview (SASII); ratings of suicidality (OAS) Secondary outcomes Economic outcomes: service use (indirect economic outcome) Anger: State Trait Anger Expression Inventory (STAXI) Mental state: Clinical Outcomes in Routine Evaluation‐Outcome Measure (CORE‐OM) total score and PTSD symptoms Other outcomes Dissociative experiences: Dissociative Experiences Scale (DES)
Notes	a11/41 of randomised participants (27%) had a diagnosis of AsPD; no data for AsPD subsample bDue to comorbidity of personality disorders, percentages summed to more than 100%. Study funding: Camden and Islington Health Authority and North Thames Regional Health Authority Declaration of interests: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Treatment allocation was made offsite via telephone randomization using a stochastic minimization programme (MINIM) balancing for sector within the regions to avoid differences in terms of differential referral practices, gender, and presence of BPD." (p 124)
Allocation concealment (selection bias)	Low risk	Quote: "Treatment allocation was made offsite via telephone randomization using a stochastic minimization programme (MINIM) balancing for sector within the regions to avoid differences in terms of differential referral practices, gender, and presence of BPD. Clients were randomized so that two of three entered DBT and one of three TAU in order to build the caseloads for staff, as this was a new service with no existing clients." (p 124)
Blinding (performance bias and detection bias) of participants	High risk	Comment: In a study such as this, full blinding is difficult to achieve because participants would be aware whether or not that they were participating in a psychological intervention and may also be aware of the nature of this intervention. Quote: "Patients in the TAU group were informed that they would receive DBT in 1 year, if they still wished for this therapy." (p 125) Comment:The review authors considered that this statement increased the risk of bias that might result from differential behaviours by participants in the TAU and DBT groups.
Blinding (performance bias and detection bias) of personnel	Unclear risk	Comment: In a study such as this, full blinding is difficult to achieve because personnel would be aware whether or not they were participating in a psychological intervention and may also be aware of the nature of this intervention. The review authors judged that it would thus not be possible to fully blind personnel in this type of study.
Blinding (performance bias and detection bias) of outcome assessors	High risk	Quote:"...while we attempted blinding of assessments, as is often the case with psychosocial treatment trials, those carrying out the research assessments could mostly identify the treatment group of the patient." (p 137)
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment:The trial investigators reported DBT data withdrawal (n = 1) and conducted an ITT analysis. The paper did not provide adequate information on statistical processes to make a judgement of Yes or No.
Selective reporting (reporting bias)	Unclear risk	Comment: It was unclear if the study was subject to selective reporting as no protocol was available. It should be noted however that there was considerable time between the study completion and publication of the results in a peer‐reviewed journal.
Other bias	Unclear risk	Comment: Attention bias: treatment offered in TAU was not carefully examined ‐ unlike the DBT condition. Allegiance bias: the trial investigators provided components of DBT (individual, group, generalisation – through phone coaching – and consultation to the environment), but this was not fully adherent to the DBT programme, since telephone consultation was not provided for the full 24‐hr day for all clients. Also, potential allegiance bias of author (JF) for DBT treatment. Other: extensive use of self‐report measures (little or no opportunity for cross‐referencing validation checks); especially problematic for suicide/service use.