Methods	Allocation: random, no further details. Blindness: double, identical capsules. Duration: 52 weeks (26 weeks observed, because of small group sizes). Design: parallel. Location: multicentre. Country: USA.
Participants	Diagnosis: (DSM-IV) schizophrenia, inadequate efficacy in previous study, clozapine treatment (n=49) was open-label. N=99, (observed N=50). Age: 18-65 years (mean=39.7 years). Sex: 80 M, 19 F. History: duration ill, age at onset, not reported. Setting: in- and outpatient.
Interventions	Olanzapine: flexible dose. Allowed dose range: 7.5-30 mg/day. Mean dose: 23.4 mg/day. N=19. Quetiapine: flexible dose. Allowed dose range: 200-800 mg/day. Mean dose: 642.9 mg/day. N=15. Risperidone: flexible dose. Allowed dose range: 1.5-6 mg/day. Mean dose: 4.8 mg/day. N=16
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Global state: CGI. Mental State: PANSS total score, PANSS positive subscore, PANSS negative subscore. Adverse effects: open interviews, amenorrhoea, galactorrhoea, sexual dysfunction, sedation, laboratory (lipids, glucose, prolactin, haemoglobin A1C level), weight gain Unable to use - Global state CGI: no 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? Objective outcomes	Low risk	Objective outcomes such as laboratory measures or death are unlikely to have been much affected by problems of blinding
Blinding? Subjective outcomes	Unclear risk	Double, identical capsules. Whether blinding was successful has not been examined, but the compounds differ quite substantially in side-effects. This can be a problem for blinding
Incomplete outcome data addressed? All outcomes	High risk	The overall attrition rate was high (74%). It is doubtful that the validity of the results was unaffected
Free of selective reporting?	High risk	Due to small numbers and the very high attrition only data on 26 weeks treatment (rather than 52 weeks) were presented
Free of other bias?	Unclear risk	Dose ranges were quite different, the upper dose range of olanzapine was 30 mg whereas risperidone could only be titrated up to 6mg /day. Patients had a history of former inefficacy to one of the medications. It was excluded that the same medication could be given again but still this might implicate a risk of bias due to baseline imbalance in terms of former treatment. There was no wash out period. Sponsorship was neutral