Background Chlorpromazine, formulated in the 1950s, remains a benchmark treatment for people with schizophrenia. Objectives To review the effects of chlorpromazine compared with placebo, for the treatment of schizophrenia. Search methods We searched the Cochrane Schizophrenia Group's Trials Register (15 May 2012). We also searched references of all identified studies for further trial citations. We contacted pharmaceutical companies and authors of trials for additional information. Selection criteria We included all randomised controlled trials (RCTs) comparing chlorpromazine with placebo for people with schizophrenia and nonaffective serious/chronic mental illness irrespective of mode of diagnosis. Primary outcomes of interest were death, violent behaviours, overall improvement, relapse and satisfaction with care. Data collection and analysis We independently inspected citations and abstracts, ordered papers, re-inspected and quality assessed these. We analysed dichotomous data using risk ratio (RR) and estimated the 95% confidence interval (CI) around this. We excluded continuous data if more than 50% of participants were lost to follow-up. Where continuous data were included, we analysed this data using mean difference (MD) with a 95% confidence interval. We used a fixed-effect model. Main results We inspected over 1100 electronic records. The review currently includes 315 excluded studies and 55 included studies. The quality of the evidence is very low. We found chlorpromazine reduced the number of participants experiencing a relapse compared with placebo during six months to two years follow-up (n=512, 3 RCTs, RR 0.65 CI 0.47 to 0.90), but data were heterogeneous. No difference was found in relapse rates in the short, medium or long term over two years, although data were also heterogeneous. We found chlorpromazine provided a global improvement in a person's symptoms and functioning (n=1164, 14 RCTs, RR 0.71 CI 0.58 to 0.86). Fewer people allocated to chlorpromazine left trials early (n=1831, 27 RCTs, RR 0.64 CI 0.53 to 0.78) compared with placebo. There are many adverse effects. Chlorpromazine is clearly sedating (n=1627, 23 RCTs, RR 2.79 CI 2.25 to 3.45), it increases 1 Chlorpromazine versus placebo for schizophrenia (Review)
