Methods	Allocation: random, medication containers according to a pseudo-random computer algorithm. Blindness: double, no further details. Duration: 8 weeks. Design: parallel. Location: single centre. Country: Germany.
Participants	Diagnosis: (DSM-IV and ICD-10) schizophrenia, CGI of 4 or more, PANSS of 61 or more. N=52. Age: 18-65 years (mean amisulpride=38.3 years, mean olanzapine=34.3 years). Sex: 23 M, 13 F (of subjects with neuropsychological data, n=36). History: duration ill mean=8.4 years (of subjects with neuropsychological data, n=36), age at onset 27.9 years (of subjects with neuropsychological data, n=36). Setting: inpatient.
Interventions	Amisulpride: flexible dose. Allowed dose range: 400-800 mg/day. Mean dose: 511.1 mg/day. N=26. Olanzapine: flexible dose. Allowed dose range: 10-20 mg/day. Mean dose: 15.0 mg/day. N=26
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Global State: CGI. Mental State: PANSS total score, PANSS positive subscore, PANSS negative subscore, SANS total score. Cognitive Functioning: Global Cognitive Index total score, trail making test A & B, continuos performance test, seld ordered pointing task, Rey auditory verbal learni g test. Adverse effects: EPS (SAS).
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Random, medication containers according to a pseudo-random computer algorithm
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 both compounds differ quite substantially in side-effects. This can be a problem for blinding
Incomplete outcome data addressed? All outcomes	High risk	The rate of participants leaving the study early was high (50%). The last-observa-tion-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 and lead to bias in cases of high attrition
Free of selective reporting?	High risk	Additional treatment with biperiden up to 4mg/day was permitted, but data on use of antiparkinson medication was not available
Free of other bias?	High risk	The study was sponsored by the manufacturer of olanzapine.