Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom severity
Systematic review	215 people 5 RCTs in this analysis	Mean difference in Scale for the Assessment of Negative Symptoms (SANS) score short term with clozapine (25–900 mg/day) with haloperidol (10–30 mg/day), chlorpromazine (50–1800 mg/day) Absolute results not reported	Mean difference –7.12 95% CI –8.78 to –5.46	Effect size not calculated	clozapine
Systematic review	235 people Data from 1 RCT	Mean difference in Positive and Negative Syndrome Scale (PANSS) negative symptom score long term with clozapine (100–900 mg/day) with haloperidol (5–30 mg/day) Absolute results not reported	Mean difference –0.90 95% CI –6.63 to +4.83		Not significant
Systematic review	60 people Data from 1 RCT	Mean difference in Scale for the Assessment of Positive Symptoms (SAPS) endpoint score short term with clozapine (300 mg/day) with chlorpromazine (500 mg/day) Absolute results not reported	Mean difference +4.39 95% CI –12.15 to +20.93		Not significant
Systematic review	235 people Data from 1 RCT	Mean difference in PANSS positive symptoms endpoint score long term with clozapine (100–900 mg/day) with haloperidol (5–30 mg) Absolute results not reported	Mean difference –2.20 95% CI –3.27 to –1.13	Effect size not calculated	clozapine
Systematic review	82 people Data from 1 RCT	Cognitive functioning: impairment (SKT) short term with clozapine (mean 350 mg/day) with haloperidol (mean 16 mg/day) Absolute results not reported	RR 0.56 95% CI 0.34 to 0.92	Small effect size	clozapine
Systematic review	1080 people 10 RCTs in this analysis	Hedges' adjusted g effect size for positive symptoms (PANSS) with clozapine with first-generation antipsychotics Absolute results not reported	Effect size –0.36 95% CI –0.56 to –0.16	Effect size not calculated	clozapine
Systematic review	1603 people 17 RCTs in this analysis	Hedges' adjusted g effect size for negative symptoms (PANSS) with clozapine with first-generation antipsychotics Absolute results not reported	Effect size –0.27 95% CI –0.42 to –0.13	Effect size not calculated	clozapine