Methods	Allocation: random, no further details. Blindness: double, no further details. Duration: 28 weeks. Design: parallel. Location: multicentre. Countries: Belgium, France, Germany, The Netherlands, South Africa, Spain, Switzerland, UK, USA
Participants	Diagnosis: (DSM-IV) schizophrenia (n=277), schizophreniform disorder or schizoaffective disorder, BPRS score of 42 or more. N=339. Age: 18-65 years (mean=36.21 years). Sex: 220 M, 119 F. History: duration ill not reported, age at onset mean=23.7 years. Setting: in- and outpatient.
Interventions	Olanzapine: flexible dose. Allowed dose range: 10-20 mg/day. Mean dose: 17.2 mg/day. N=172. Risperidone: flexible dose. Allowed dose range: 4-12 mg/day. Mean dose: 7.2 mg/day. N=167
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Mental State: PANSS total score, BPRS total score, PANSS positive subscore, PANSS negative subscore, SANS total score. Quality of life: QLS total score. Adverse effects: open interviews, cardiac effects (ECG), death (any reason, suicide attempt), EPS (akathisia, akinesia, dyskinesia, dystonia, extrapyramidal symptoms, parkinsonism, tremor, use of antiparkinson medication), Prolactin associated side effects (abnormal ejaculation, abnormally high prolactin value, amenorrhoea, decreased libido, galactorrhoea, gynaecomastia, impotence), sedation, backache, blurred vision, breathing difficulties, early wakening, nightmares, seizures, weight gain, laboratory (glucose, white blood cell count)
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, 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
Incomplete outcome data addressed? All outcomes	High risk	The attrition rate was high (47.5 %). The last-observation-carried-forward 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, given the rather high number of attrition
Free of selective reporting?	High risk	Adverse effects were only reported in the case of a significant difference between groups, therefore important side effects may have been missed by this procedure
Free of other bias?	High risk	The study was sponsored by the manufacturer of olanzapine.