Methods	Allocation: randomised. Blindness: double. Duration: 6 weeks.
Participants	Diagnosis:(DSM-III-R) schizophrenia catatonic, hebephrenic, paranoid or residual. N=50. Age: 18-60 years. Gender: not reported. History: BPRS >40 after washout phase, no previous treatment with either medication
Interventions	Clozapine: flexible dose, allowed range 150-450 mg/day. N=25. Zotepine: flexible dose, allowed range 150-450 mg/day. N=25
Outcomes	Leaving the study early: any reason. Unable to use: CGI, BPRS, SANS, adverse events: ECG, weight gain (matched samples)
Notes
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Quote: “They were randomly assigned..” Comment: Incomplete information.
Allocation concealment?	No	Probably not done.
Blinding? All outcomes	Yes	Quote: “They were randomly assigned in a double design to clozapine or zotepine” Comment: Probably done. The success of blinding was not evaluated
Incomplete outcome data addressed? All outcomes	No	7/25 missing from clozapine and 10/25 missing from zotepine. ITT was not performed
Free of selective reporting?	No	Quote: “Analysis refers to a sub-sample of 26 patients, (matched for age).” Comment: Data from sub sample was not used in our review.
Free of other bias?	Unclear	Quote: “This study was sponsored and monitored by Klinge Pharma (manufacturer of zotepine)”