Blum 2008.

Study characteristics
Methods	design: randomised controlled trial
Participants	sex: 103/124 females, i.e. 83.1% age: 31.5 years on average, SD = 9.5 location: USA setting: outpatient exclusions: not speaking English, psychotic or primary neurological disorder, cognitively impaired patients, current substance abuse or dependence, participated in STEPPS treatment previously level of functioning/severity of illness: baseline CGI‐S = 5.1 (SD = 0.8) in EG, baseline CGI‐S = 4.9 (SD = 0.9) in CG; i.e. patients were "markedly ill" BPD diagnosis according to: DSM‐IV means of assessment: SIDP‐IV
Interventions	group 1 (EG): STEPPS: 20 2‐hour weekly group therapy sessions + homework assignments + 1 session for family members or significant others; no individual therapy group 2 (CG): Treatment as usual (TAU): subjects were encouraged to continue their usual care, including individual psychotherapy, medication, and case management duration: 20 weeks concomitant psychotherapy: participants were encouraged to continue with ongoing concomitant treatments. 59% of all participants had an additional individual therapy (EG: 63%, CG: 54%; difference not significant) concomitant pharmacotherapy: 90% of subjects reported at least one psychotropic medication at baseline; on average, participants received 2.9 psychotropic medications, SD = 2.3 (EG: 3.0, SD = 2.5; CG: 2.7, SD = 2.1; difference not significant)
Outcomes	outcomes considered in this review self‐rated: BPD total severity (BEST), Barratt Impulsiveness Scale (BIS), depression (BDI), general psychopathology (SCL‐90‐R‐GSI) observer‐rated: affective instability (ZAN‐BPD‐affective subscale), interpersonal problems (ZAN‐BPD‐disturbed relationships subscale), cognitive disturbance (ZAN‐BPD‐cognitive subscale), mental health status (CGI‐S) time‐points used here: week 20 (post treatment)
Notes	analysis: ITT of those actually having received allocated intervention, regardless of completion or noncompletion. However, 40 participants that had been randomly allocated did not receive the allocated intervention and were not included in analyses. "Subjects with at least one postbaseline assessment were included in the analyses." (Blum 2008, p. 470).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Subjects were assigned by coin toss" (Blum 2008, p. 469)
Allocation concealment (selection bias)	Low risk	No indication of bias.
Blinding of outcome assessment (detection bias) All outcomes	High risk	"While we intended to conduct blind assessments, we found it nearly impossible to maintain blindness. The convergence of both rater‐ and patient‐administered scales suggests that this may not have been an important deficiency." (Blum 2008, p. 477).
Selective reporting (reporting bias)	Unclear risk	Study protocol is available, but there is no information about primary or secondary outcomes. The authors report a broad range of outcomes, so there is no indication for selective reporting given. However, there is insufficient information to permit judgment of 'Yes' or 'No'.
Treatment adherence?	Low risk	"Adherence to the manual was rated on a 5‐point scale [...] A score of 4 (good) or higher was considered acceptable. Two Ph.D.‐level psychologists who were not involved with the randomized controlled trial but familiar with STEPPS rated 43 randomly selected video‐taped session. The mean adherence score was 4.4 (SD = 0.8)."
Allegiance effect improbable?	High risk	There is no indication given for an allegiance effect. However, as some authors are founders of STEPPS, the treatment actually used in the experimental group, an allegiance effect seems not improbable.
Attention bias: equal amounts of attention to all groups (obligatory treatment components)?	High risk	More attention paid to EG participants.