Content and quality of 2000 controlled trials in schizophrenia over 50 years

Objective To provide a comprehensive survey of the content and quality of intervention studies relevant to the treatment of schizophrenia. Design Data were extracted from 2000 trials on the Cochrane Schizophrenia Group's register. Main outcome measures Type and date of publication, country of origin, language, size of study, treatment setting, participant group, interventions, outcomes, and quality of study. Results Hospital based drug trials undertaken in the United States were dominant in the sample (54%). Generally, studies were short (54% < 6 weeks), small (mean number of patients 65), and poorly reported (64% had a quality score of less than or equal to 2 (maximum score 5)). Over 600 different interventions were studied in these trials, and 640 different rating scales were used to measure outcome. Conclusions Half a century of studies of limited quality, duration, and clinical utility leave much scope for well planned, conducted, and reported trials. The drug regulatory authorities should stipulate that the results of both explanatory and pragmatic trials are necessary before a compound is given a licence for everyday use.