McMurran 2016.

Study characteristics
Methods	12‐week trial with 2 arms Psychoeducation and problem solving (PEPS) therapy, internet‐based control group with no psychoeducation + treatment‐as‐usual (TAU) TAU Duration of trial: 12 weeks Country: UK Setting: community (outpatient)
Participants	Methods of recruitment of participants: referred to PEPS team. Participants were recruited from mental health services in 3 UK NHS trusts. Sample size: subsample = 183 Diagnosis of borderline personality disorder: Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM‐IV) Means of assessment: International personality disorder examination (IPDE) Mean age: no data on subsample. Full sample for PEPS therapy = 38.6 years (standard deviation = 10.9), full sample for TAU = 37.8 years (standard deviation = 11) Sex: approximately 75% female Comorbidity: not stated Inclusion criteria At the point of randomisation, participants were required to have one or more personal disorder(s) (including personality disorder not otherwise specified), identified through the IPDE (Loranger 1995) Aged 18 years or over Living in the community Proficient in spoken English Had capacity to provide informed consent Exclusion criteria A primary diagnosis of major functional psychosis Insufficient degree of literacy Incomprehension or lack of attention to be able to engage in trial therapy and assessments Engagement in a specific programme of psychological treatment for personality disorder or likely to start such treatment during the trial period Participation in any other trial
Interventions	Experimental group Treatment name: PEPS therapy, internet‐based control group with no psychoeducation + TAU Number randomised to group: 93 Duration: 12 weeks Control/comparison group Comparison name: TAU Number randomised to group: 90 Duration: 12 weeks Both groups Concomitant psychotherapy: not stated Concomitant pharmacotherapy: allowed Proportions of participants taking standing psychotropic medication during trial observation period: unclear
Outcomes	Primary Psychosocial functioning, assesed by the Social Functioning Questionnaire (SFQ) Secondary Depression, assessed by the Hospital Anxiety and Depression Scale (HADS) Attrition, in terms of patients lost after randomisation in each group Adverse effects (AE), as assessed by the total number of adverse effects in each group. AE was defined as death for any reason, inhospitalisation for any reason and any other serious, unexpected AE.
Notes	Sample size calculation: yes Ethics approval: yes Comments from review authors: We received additional data on BPD subgroups by email from Dr Murran in 2017 and again in 2018.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomisation was based on a computer generated pseudo‐random code using random permuted blocks of randomly varying size created by the Nottingham Clinical Trials Unit [NCTU] in accordance with their standard operating procedure and held on a secure server. Allocation was stratified by recruiting centre and sex." (p xxiv)
Allocation concealment (selection bias)	Low risk	Quote: "The sequence of treatment allocations was concealed until recruitment, data collection, and all other trial‐related assessments were complete. The investigator, or an authorised designee, accessed the treatment allocation for each participant by means of a remote, internet‐based randomisation system developed and maintained by the NCTU. Allocation was therefore fully concealed from recruiting staff." (p 14)
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "At the start of each follow‐up, participants were reminded of the importance of not disclosing their treatment allocation to the research assistant using a suggested unblinding script (See Appendix 9). If the research assistant was inadvertently unblinded to treatment allocation before completing the final follow‐up, a record of the incident of unblinding was made. Researchers also reported whether or not they were aware of the treatment allocation at the time of completing the primary end‐point assessments. Owing to changes in personnel over the course of the trial, in some cases, end‐point assessments were conducted by researchers who were not unblinded. A record was made of the blinding status of the researcher conducting the final follow‐up data collection." (p 16). "Data analysts remained blinded to allocation during the study by having access to only aggregate data and no access to data that could reveal treatment arm, such as course attendance". "Most of the outcome data were obtained from self‐report questionnaires from participants who were not blind to treatment allocation". (p 16)
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: Participants were analysed as randomised, and all were included in the primary analysis by imputation of missing data. Quotes: "We obtained robust variance estimates in all regression models to allow for the potential clustering effect of receiving therapy in groups in the PEPS arm." (p 8) "The primary analysis (ITT) compared the mean SFQ score between PEPS and usual treatment at 72 weeks postrandomisation follow‐up, adjusted for baseline SFQ score and stratification variables (centre and gender), and implemented using maximum likelihood‐based generalised linear modelling." (p 12) "The pattern of missing data was investigated by examining variables recorded at baseline that were associated with ‘missingness’ of SFQ score at the 72‐week follow‐up. Multiple imputation and analysis of multiple imputed data sets were conducted using ‘mi’ procedures in Stata. The imputation model contained site, age, sex,ethnicity, social status, PD category (simple or complex), SFQ at baseline and 24 weeks, baseline EQ‐5D health state score, baseline HADS score, baseline SPSI‐R score and baseline three main problems score, and 20 data sets were imputed." (p 12)
Selective reporting (reporting bias)	Low risk	Comment: in terms of outcomes, protocol and full‐text report matched.
Other bias	High risk	Treatment adherence Comment: adherence was self‐rated by the therapist. Attention bias Comment: mean number of treatment weeks: TAU non‐completer = 30 (SD = 25.7), completer = 80.2 (SD = 9,8); PEPS non‐completer = 36.7 (SD = 23,4), completer = 80.3 (SD = 10.4). Seemed that both groups got equal amount of therapy. Allegiance bias Comment: authors (MM, CD) have allegiance to PEPS therapy. Vested interest Comment: The National Institute for Health Research (NIHR) Health Technology Assessment programme funded this study. Hywel Williams is the Deputy Director of this programme but was not involved in the funding decision for this programme.