Methods	Allocation: randomised - ball drawing out of box. Blindness: double. Duration: 12 weeks.
Participants	Diagnosis:(CCMD-3) schizophrenia. N=120 Age: mean clozapine=33.5 years, mean risperidone=35.4 years. Gender: not reported. Setting: outpatient. History duration ill: clozapine: 6.2 years risperidone 6.4 years
Interventions	Clozapine: mean dose: 350 mg/day.N=60 Risperidone:mean dose: 3.2 mg/day.N=60
Outcomes	Mental state: PANSS positive and negative subscore.
Notes
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	Allocation: random, ball drawing out of a covered box. Probably yes
Allocation concealment?	Unclear	No further details.
Blinding? All outcomes	Unclear	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 Objective outcomes such as laboratory measures or death are unlikely to have been much affected by problems of blinding. This latter, probably leads a low risk of bias
Incomplete outcome data addressed? All outcomes	No	Data on leaving the study early were not provided.
Free of selective reporting?	No	Secondary outcomes were poorly reported.
Free of other bias?	Unclear	The allowed dose ranges were not indicated.