Cullen 2012.

Study characteristics
Methods	Allocation: randomised Blindness: unblinded; researchers were not blind to group status. Duration: 3 to 4 months, further 12‐month follow‐up post treatmentdesign: superiority, parallel group, randomised trial, multisite Country: UK
Participants	Diagnosis: DSM‐IV or ICD‐10 criteria for schizophrenia (n = 69), schizoaffective disorder (n = 0) or other psychotic disorder ( = 5) N =84 Age: mean age 35.4 years (SD = 10) Sex: all participants were male. History: history of violent behaviour leading to the current admission Ethnicity: 50% African or African‐Caribbean, 32% white, 18% other Setting: medium‐secure forensic units in psychiatric hospitals Exclusion: having participated in R&R or a similar programme previously, actively psychotic, presence of significant cognitive impairments, and not having sufficient proficiency in English
Interventions	R&R programme (N = 44) plus TAU TAU programme (N = 40)
Outcomes	Short term (end of treatment:3 to 4 months): Aggression – frequency of aggressive episodes: rate ratio of physical violence computed from case notes Aggression – frequency of aggressive episodes: rate ratio of verbal aggression computed from case notes Medium term (12‐month post‐treatment): Aggression – frequency of aggressive episodes: rate ratio of physical violence computed from case notes Aggression – frequency of aggressive episodes: rate ratio of verbal aggression computed from case notes
Notes	Trial registration: ISRCTN 46561083 Funding: NHS National Research and Development programme on Forensic Mental Health, UK Declaration of interest: none Contact of authors: not pursued; the study was reported extensively in 3 independent publications.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Within each site, participants were randomly allocated (1:1) to interventions with block randomisation stratified by centre using equal block sizes.
Allocation concealment (selection bias)	Low risk	Randomisation was done for a yet recruited cohort which controlled for allocation concealment. Only after randomisation, the research team of each unit were informed of the allocation status for each participant.
Blinding of participants and personnel (performance bias) All outcomes	High risk	The interventions delivered in this study do not permit to blind them to participants and personnel.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Researchers were not blind to allocation status, as this was often revealed in the clinical notes or by the patients themselves.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Overall, the attrition rate was low for the outcomes of interest; 42 of 44 participants in the R&R group provided information at end of treatment (4.5% attrition), whereas all 40 participants randomised to TAU provided information (0% attrition). At 12‐month post‐treatment, 42 of 44 participants in the R&R group provided information (4.5% attrition) as well as 38 of 40 participants in the TAU group (5% attrition).
Selective reporting (reporting bias)	Unclear risk	This study has a retrospective trial registration, and this makes unclear if all prespecified outcomes have been reported.
Other bias	Low risk	No other source of bias was identified.