Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom severity
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) Absolute results not reported	Mean difference –0.90 95% CI –6.63 to +4.83		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 (Syndrome kurz test [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