Schizophrenia is a long-term illness with a worldwide lifetime prevalence of about one per cent. Many people who suffer from schizophrenia live with considerable disability. Chlorpromazine was one of the first drugs discovered to be effective in its treatment back in the 1950s - and is still used extensively today.
This review updates the information available from trials in which chlorpromazine was compared with placebo. In addition it attempts to look at outcomes in smaller sub-groups of people, by sex, by age, by length of illness, by dose of chlorpromazine, by criteria of diagnosis or by whether they were diagnosed before or after 1990. This update adds one study giving a total of 50 studies and the included data have been divided as to whether they refer to short, medium or long-term treatment. When looking at chlorpromazine versus placebo for schizophrenia since the first review in 1995, 349 trials have been considered but 299 have been excluded because of flaws in the research methods or the reporting of the data. This is a shame and much opportunity has been lost to report outcomes of interest to the reviewers and others.
Chlorpromazine has been shown to improve both a person’s symptoms and functioning in 13 trials containing 1121 people. Chlorpromazine reduces relapse in the short, medium and long term. Many trials, however, have demonstrated that chlorpromazine has a number of adverse effects when compared with placebo important ones being movement disorders, sleepiness, skin sensitivity to sunlight, low blood pressure and constipation. The main weakness of these trials is that the majority are conducted on people who are in hospital. The results, therefore, may, at best, be only partially applicable to people in the community.
(Plain language summary prepared for this review by Janey Antoniou of RETHINK, UK www.rethink.org).