Methods	Allocation: random, no further details. Blindness: double, no further details. Duration: 52 weeks. Design: parallel. Location: multicentre. Country: not reported.
Participants	Diagnosis: (DSM-IV) schizophrenia (n=231), schizophreniform disorder (n=115) or schizoaffective disorder (n=54), first episode, psychotic symptoms for 1 month to 5 years, PANSS psychosis and CGI-S score of 4 or more. N=400. Age: 16-40 years (mean=24.5 years). Sex: 292 M, 108 F. History: duration ill mean=1.08 years, age at onset 23.5 years. Setting: in- and outpatient.
Interventions	Olanzapine: flexible dose. Allowed dose range: 2.5-20 mg/day. Mean dose: 11.7 mg/day. N=133. Quetiapine: flexible dose. Allowed dose range: 100-800 mg/day. Mean dose: 506 mg/day. N=134. Risperidone: flexible dose. Allowed dose range: 0.5-4 mg/day. Mean dose: 2.4 mg/day. N=133
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Global State: CGI. Mental State: PANSS total, PANSS positive subscore, PANSS negative subscore, depression Calgary depression scale. Adverse effects: open interviews, death (suicide attempt, suicide, EPS (akathisia, akinesia, use of antiparkinson medication, laboratory (cholesterol, fasting glucose, prolactin) , prolactin associated side effects (amenorrhoea, galactorrhoea, gynaecomastia, sexual dysfunction), sedation, insomnia, dry mouth, orthostatic faintness, constipation, sialorrhoea, skin rash, gynaecomastia, urinary hesitancy, incontinence, weight gain (BMI, waist circumference)
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 (70.3.%). Analysis was based on mixed effects model and secondary on last-observation-carried forward and observed cases. It is unclear whether any statistical method can account for such a high drop-out rate
Free of selective reporting?	High risk	Adverse events were presented only in case of moderate or worse severity
Free of other bias?	High risk	The study was sponsored by the manufacturer of quetiapine.