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

Abstract

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 <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.

RCTs in psychiatry: challenges and the future

“…For example, a study of over 2000 trials in schizophrenia found that the mean sample size was about 60 (Thornley & Adams, 1998). And although Johnson (1998) from a search of the four leading psychiatric journals from 1956 thorough to 1996 found that the number of patients per treatment group in psychiatric trials was indeed rising over the four decades, the increase, from 17 to 25 over 40 years, was hardly impressive!…”

“…Psychiatrists also use far too many rating scales to measure far too many things in their trials, increasing the chances of false positive findings (as the Oxford, UK, group of trialists note, "many trials would be of much greater scientific value if they collected 10 times less data on 10 times more patients"). An analysis of trials on the Cochrane Schizophrenia Database found that over 640 different rating scales had been employed (Thornley & Adams, 1998: Gilbody et al, 2002. The use of a large number of outcome measures is driven by the fear of missing something that might be "clinically significant" even if that 'something' was not the primary reason for carrying out the study.…”

The CONSORT statement: Revised recommendations for improving the quality of reports of parallel-group randomized trials 2001

“…Despite several decades of educational efforts, RCTs still are not being reported adequately, [3][4][5][6]. For example, a review, [5] of 122 recently published RCTs that evaluated the effectiveness of selective serotonin reuptake inhibitors (SSRI) as first-line management strategy for depression found that only one (0.8%) paper described randomization adequately.…”

Large simple trials in psychiatry: providing reliable answers to important clinical questions

“…It is probably true to say that trials in mental health need to be much larger than they currently are (Hotopf et al, 1997;Thornley & Adams, 1998).…”