Methods	Allocation: randomised. Blindness: double. Duration: 18 weeks.
Participants	Diagnosis: (DSM-IV) schizophrenia catatonic (N=3), disorganised (N=34), paranoid (N=101), residual (N=8) or undifferentiated (N=34), previous treatment resistance. N=180 Age: 18-70 years (mean=38.6 years). Gender: 115 M, 65 F. Setting: in- and outpatient. History: duration ill not reported, age at onset mean=22.8 years
Interventions	Clozapine: flexible dose. Allowed dose range: 200-600 mg/day.Mean dose: 303.6 mg/day. N=90. Olanzapine: flexible dose. Allowed dose range: 15-25 mg/day. Mean dose: 20.5 mg/day. N=90
Outcomes	Leaving the study early: any reason, adverse events, inefficacy. Mental state: clinical improvement (at least 20%BPRS reduction+CGI-S<3 or BPRS<35) ( > or = 50% reduction on PANSS total), PANSS total, positive and negative subscore, BPRS total score. Adverse effects:extrapyramidal effects (SAS, AIMS, BAS), prolactin levels, weight change
Notes
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Quote: “patients were randomly allocated in a 1:1 ratio to treatment with olanzapine 15-25 mg/day or clozapine 200-600 mg/day” Comment: Incomplete information.
Allocation concealment?	No	No information. Probably not done.
Blinding? All outcomes	Yes	Quote: “An 18-week double-blind therapy” Comment: Probably done. The success of blinding was not evaluated
Incomplete outcome data addressed? All outcomes	No	37/90 missing from clozapine and 36/90 missing from olanzapine Quote: “All end point analyses used a last observation carried forward (LOCF) algorithm” Comment: OC technique for weekly measures of patients with at least one post-baseline measurement. ITT analysis was not performed
Free of selective reporting?	No	Spontaneously Reported Treatment-Emergent Adverse Events with an Incidence of ≥5% in either Treatment Group, or with a statistically significant difference (P< .05) between treatment Groups. Solicited treatment-emergent adverse events with statistically significant difference
Free of other bias?	Yes	Review authors have not found other sources of bias.