Much to improve: A survey of controlled Nordic schizophrenia trials

Abstract

The Cochrane Schizophrenia Group's Register of Trials was surveyed for reports on trials of Nordic origin. Quality assessment of reports was undertaken in accordance with the Jadad scale. Two hundred and twenty reports covering 181 trials from four Nordic countries were found, with most originating from Sweden. The Nordic trials were smaller than those from other countries and with a few exceptions had inadequate statistical power to produce any precise conclusions. Interventions applied were almost entirely biologic. Even though about half of the Nordic trial reports were of low quality, the mean quality score of these reports was significantly better than that of the rest of the world (U=147260, df=2035, P=0.017). In the future trials should be designed to recruit adequate sample sizes to be able to provide clinically useful data, and trial reporting must be improved. The use of prospective controlled trials should be extended to evaluation of psychosocial treatments of schizophrenia.