Methods	Allocation: random, no further details. Blindness: double, no further details. Duration: 26 weeks. Design: parallel. Location: multicentre. Countries: not reported.
Participants	Diagnosis: (DSM-IV) schizophrenia catatonic (n=11), disorganised (n=102) or residual (n=131) (of intent-to-treat population), SANS severity score of 10 or more (excluding the item attention). N=245. Age: mean amisulpride=37.8 years, mean olanzapine (5 mg/day)=38.1 years, mean olanzapine (20 mg/day)=36.4 years, mean placebo=38.2 years. Sex: 167 M, 78 F. History: duration ill mean amisulpride=12.33 years, mean olanzapine (5 mg/day)=10. 08 years, mean olanzapine (20 mg/day)=11.08 years, mean placebo=15.42 years, age at onset not reported. Setting: in- and outpatient.
Interventions	Amisulpride: fixed dose: 150 mg/day. N=70. Olanzapine: fixed dose: 5 mg/day. N=70. Olanzapine: fixed dose: 20 mg/day. N=70.
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Global State: CGI, relapse, Patient’s global impression. Mental State: PANSS total score, BPRS total score, PANSS positive subscore, PANSS negative subscore, SANS total score, Psychotic depression Scale. Quality of life: Carpenters QLS total score. Adverse effects: EPS (akathisia, akinesia, parkinsonism, tremor), prolactin associated side effects, sedation, seizures, weight, laboratory (leukopenia)
Notes	There is a placebo group (n=35), which is not relevant for this review
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 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 leaving the study early was high (57.6%). 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 and poses problem given the high attrition
Free of selective reporting?	High risk	Only those adverse events were reported that occurred with an incidence of at least 10%, therefore rare but important side effects may have been missed by this procedure
Free of other bias?	High risk	The study was industry sponsored by the manufacturer of olanzapine and one of the authors is employee of that company. A fixed dose regimen was used where it might be difficult to decide which comparator doses are appropriate