Cook 2012a.

Methods	Allocation: randomised Blindness: single blinded Study duration: 40 weeks Location: multicentre Design: parallel Setting: outpatient Country: USA Consent: written
Participants	Diagnosis: schizophrenia 15.4%, schizoaffective 5.4%, bipolar 39.5%, depressive 18% and other 18.6% N = 428 History: ≥ 12 months Sex: men 190, women 238 Age: mean 42.8, SD 10.9 years Exclusion criteria: not stated
Interventions	Group 1: peer‐support + standard care (n = 212). Content: peer‐led, mental illness education intervention called Building Recovery of Individual Dreams and Goals through Education and Support (BRIDGES). Classes were delivered interactively, and included group discussion, illustrative anecdotes and structured exercises designed to apply information to everyday situations. Course topics included recovery principles and stages, strategies for building interpersonal and community support systems, brain biology and psychiatric medications, diagnoses and related symptom complexes, traditional and non‐traditional treatments and relapse prevention and coping skills. Delivered by: peers who were certified BRIDGES instructors in recovery from severe mental illness. Frequency: 2.5‐hour classes delivered weekly for 8 weeks. Treatment duration: 8 weeks. Group 2: standard care (n = 216). Content: participants were assigned to a course waiting list and guaranteed an opportunity to receive BRIDGES once their final interview ended. Otherwise, they continued to receive services as usual. Treatment duration: 8 weeks.
Outcomes	Mental state: hope, other specific aspects Behaviour: recovery, other specific aspects Unable to use Global state: leaving the study early (author did not report data by each group separately) Mental state: depression – BSI, personal empowerment, self‐advocacy and coping style (data not reported)
Notes	Funding source: US Department of Education, National Institute on Disability and Rehabilitation Research; and the Substance Abuse & Mental Health Services Administration, Center for Mental Health Services, Cooperative Agreement (H133B050003B). We contacted the author to clarify whether peer support group received standard care; however, we received no reply. Therefore, from a prospective of a clinician, the peer support group should have received standard care.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "random assignment occurred using computer‐assisted block randomisation stratified according to centre." Comment: adequate sequence generation.
Allocation concealment (selection bias)	Low risk	Quote: "A random allocation sequence that was programmed into the Computer Assisted Personal Interviewing (CAPI) administration software guaranteed allocation concealment up to the point of assignment." Comment: participants could not foresee the assignment.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "interviewers were blinded to subjects' study condition assignment." Comment: blinding of personnel was likely to be broken, no blinding information for participants.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "interviewers were blinded to subjects' study condition assignment." Comment: blinding of assessors ensured.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: "of 212 experimental subjects, 161 (76%) received the intervention and 51 (24%) did not." Comment: moderate attrition rate.
Selective reporting (reporting bias)	High risk	Comment: study protocol registered on ClinicalTrials.gov (NCT01297985). However, the personal empowerment, self‐advocacy and coping style data were not reported.
Other bias	Low risk	None noted.