Methods	Allocation: random, no further details. Blindness: double, no further details. Duration: 8 weeks (last 4 weeks observed). Design: parallel. Location: single centre.
Participants	Diagnosis: (DSM-IV) schizophrenia disorganised (n = 23), paranoid (n = 10), undifferentiated (n = 34). N = 77. Sex: 39 M, 38 F. Age: 28-84 years (mean = 59.9 years). History: duration ill mean = 34.51 years, age at onset: not reported. Setting: inpatient.
Interventions	Olanzapine: flexible dose. Allowed dose range: 2.5-20 mg/day. Mean dose: 16.5 mg/day. N = 20. Perospirone: flexible dose. Allowed dose range: 4-48 mg/day. Mean dose: 37.3 mg/day. N = 18. Quetiapine: flexible dose. Allowed dose range: 50-750 mg/day. Mean dose: 432.5 mg/day. N = 20. Risperidone: flexible dose. Allowed dose range: 1-12 mg/day. Mean dose: 7.37 mg/day. N = 19
Outcomes	Mental State: PANSS total score, PANSS positive subscore, PANSS negative subscore. Cognitive functioning: digit span distractibility test.
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	Double, no further details. 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	High risk	There was no data on attrition available.
Free of selective reporting?	High risk	Adverse events were not reported. Numbers on use of antiparkinson medication have not been presented
Free of other bias?	High risk	There was no wash-out period. The previous antipsychotic treatment was gradually tapered over 4 weeks. Thus, during a period of 4 weeks the participants were on two drugs