Methods	Allocation: random, no further details. Blindness: single, rater-blinded. Duration: 16 weeks. Design: parallel. Location: multicentre.
Participants	Diagnosis: (DSM-IV) first episode schizophrenia (n = 84), schizophreniform disorder (n = 19) or schizoaffective disorder (n = 9) (of intent-to-treat population). N = 120. Sex: 78 M, 34 F (of intent-to-treat population). Age: 16-40 years (mean = 23.3 years) (of intent-to-treat population). History: duration ill mean = 2.2 years (of intent-to-treat population), age at onset mean = 20.7 years (of intent-to-treat population). Setting: not reported.
Interventions	Olanzapine: flexible dose. Allowed dose range: 2.5-20 mg/day. Mean dose: 11.8 mg/day. N = 60. Risperidone: flexible dose. Allowed dose range: 1-6 mg/day. Mean dose: 3.9 mg/day. N = 60
Outcomes	Leaving the study early: inefficacy. Global State. Adverse effects: EPS (parkinsonism, use of antiparkinson medication, Simpson-Angus) , weight gain Unable to use: Leaving the study early: incomplete data. Weight gain: 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? subjective outcomes	Unclear risk	Single-blind, rater-blinded. 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 possibly acceptable (28%), but data on leaving the study early were incompletely reported. Eight patients were excluded from the analysis for various reasons. The statistical analysis was based on mixed model approach
Free of selective reporting?	High risk	Data on the general mental state (PANSS total score) were not presented. The data available for adverse effects were incomplete. Data on weight gain were missing
Free of other bias?	Unclear risk	Quote: “.. the study was designed to detect differences in our primary analysis at alpha = 0.05 with 80% power based upon 130 subjects, the stability analysis included only 47 subjects and therefore might lack adequate power.”