Methods	Allocation: random, 2 steps of randomisation before and after availability of ziprasidone, subjects received other medication than in previous phase 1 treatment. Re-randomised. Blindness: double, identical capsules. Duration: 26 weeks. Design: parallel. Location: not reported.
Participants	Diagnosis: (DSM-IV) chronic schizophrenia. N = 444. Sex: 308 M, 136 F. Age: 18-65 years (mean olanzapine = 40.0 years, mean quetiapine = 40.1 years, mean risperidone = 41.8 years, mean ziprasidone = 41.3 years). History: duration ill not reported, age at onset not reported. Setting: in- and outpatient.
Interventions	Olanzapine: flexible dose, allowed dose range: 7.5-30 mg/day, mean dose = 20.5 mg/day. N = 108. Quetiapine: flexible dose, allowed dose range: 200-800 mg/day, mean dose = 565.2 mg/day. N = 95. Risperidone: flexible dose, allowed dose range: 1.5-6.0 mg/day, mean dose = 4.1 mg/day. N = 104. Ziprasidone: flexible dose, allowed dose range: 40-160 mg/day, mean dose = 115.9 mg/day. N = 137
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Global State: CGI. Mental State: PANSS total score. Adverse effects: open interviews, death (suicide), EPS (akathisia), cardiac effects (ECG), prolactin-associated side effects, weight gain, laboratory (prolactin, glucose, cholesterol)
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Adequate sequence generation?	Unclear risk	Random, 2 steps of randomisation before and after availability of ziprasidone, subjects received other medication than in previous phase 1 treatment. Re-randomised
Allocation concealment?	Unclear risk	No further details.
Blinding? subjective outcomes	Unclear risk	Double, identical capsules. Whether blinding was successful has not been examined, but both 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	High risk	The overall attrition was high (72.5%). The main statistical analysis used a mixed effects model approach. It is unclear whether any statistical method can account for such high rates of leaving the study early
Free of selective reporting?	High risk	Use of antiparkinson medication was permitted but data on this outcome have not been presented
Free of other bias?	Unclear risk	Patients had a history of former intolerance to atypical antipsychotic treatment but baseline data on this was not provided