Methods	Allocation: random, no further details. Blindness: double, no further details. Duration: 28 weeks. Design: parallel. Location: multicentre. Countries: not reported. (Continents: Europe, North - South America)
Participants	Diagnosis: (DSM-IV) schizophrenia, BPRS of 42 or more, CGI-S of 4 or more. N=548. Age: 18-75 years (mean olanzapine=40.1 years, mean ziprasidone=38.2 years). Sex: 352 M, 196 F. History: duration ill not reported, age at onset mean olanzapine=23.9 years, mean ziprasidone=22.8 years. Setting: in- and outpatient.
Interventions	Olanzapine: flexible dose, allowed dose range: 10-20 mg/day, mean dose=15.27 mg/day. N=277. Ziprasidone: flexible dose, allowed dose range: 80-160 mg/day, mean dose=115.96 mg/day. N=271
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Global State: CGI. Mental State: PANSS total score, PANSS positive subscore, PANSS negative subscore, PANSS cognition subscore, depression MADRS, HAMD. Quality of life: Heinrichs - Carpenter Scale. Adverse effects: open interviews, EPS (use of antiparkinson medication, dystonia, extrapyramidal symptoms, AIMS, BAS, SAS), cardiac effects (ECG), weight gain, laboratory (prolactin, glucose, lipids). Unable to use - Prolactin (no usable 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? Objective outcomes	Low risk	Double, no further details. 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 was high (48.9%). 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. Additionally mixed models analysis was performed but it is unclear whether any statistical method can account for such high numbers of leaving the study early
Free of selective reporting?	High risk	Only those adverse events that occurred in at least 10% of the participants were reported. This procedure can miss rare, but important adverse events
Free of other bias?	High risk	The study was sponsored by the manufacturer of olanzapine.