Methods	Allocation: random, no further details. Blindness: single (rater-blinded). Duration: 16 weeks (8 weeks observed). Design: parallel. Location: multicentre.
Participants	Diagnosis: (DSM-IV) schizophrenia, PANSS total score of 70 or more, PANSS positive subscore of 4 or more on at least 2 items. N = 75. Sex: M, F: not reported. Age: 18-65 years. History: duration ill not reported, age at onset not reported. Setting: inpatient.
Interventions	Olanzapine: flexible dose. Allowed dose range: 10-20 mg/day. Mean dose: 14.6 mg/day. N = 25. Quetiapine: flexible dose. Allowed dose range: 400-800 mg/day. Mean dose: 602.4 mg/day. N = 25. Risperidone: flexible dose. Allowed dose range: 4-8 mg/day. Mean dose: 4.3 mg/day. N = 25
Outcomes	Leaving the study early: any reason. Mental State: PANSS total score, BPRS hostility cluster score, PANSS positive subscore, PANSS negative subscore). Adverse effects: EPS (BAS, SAS), weight gain. Unable to use: Mental State - PANSS total score, PANSS positive subscore, PANSS negative subscore: no usable data
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Random, no further details.
Allocation concealment?	Unclear risk	No further details.
Blinding? subjective outcomes	Unclear risk	Single: rater-blind. Whether blinding was successful has not been examined, but the compounds differ quite substantially in side effects. This can be a problem for blinding
Blinding? objective outcomes	Low risk	Objective outcomes such as laboratory measures or death are unlikely to have been much affected by problems of blinding
Incomplete outcome data addressed? All outcomes	Unclear risk	The overall attrition was moderate (18.6%) . The LOCF method was used to account for people leaving the study early. It assumes that a participant who discontinued the study would not have had a change of his condition if he had remained in the study. This assumption can obviously be wrong
Free of selective reporting?	High risk	Efficacy data (PANSS) were only presented as percentage change without standard deviations, standard errors, P values or ranges. Only interim data after recruitment of half the patients have been presented
Free of other bias?	High risk	The study was sponsored by the manufacturer of quetiapine.