Translating research into clinical practice: critical interpretation of clinical trials in schizophrenia.

Translating research into clinical practice has in part been hampered by practitioners' difficulties in interpreting statistical measures. The main part of this article aims to bridge the gap between research and practice by describing frequently occurring problems in the methodology and reporting of clinical trials. Basic methodological concepts and statistical measures, such as different trial designs, randomization, blinding, case numbers, eligibility criteria, internal and external validity, efficacy versus effectiveness, the meaning of rating scales, choice of comparators, effect size versus P-value and the interpretation of risk measures, are explained and their use illustrated. The text further presents the outcome from a workshop on 'Translating Clinical Studies into Practice' held at an international conference on schizophrenia and bipolar disorder in June 2005. The participants suggested more emphasis on additional secondary endpoints in clinical trials such as patients' self assessments and indicators of well-being. Better training of clinicians in the interpretation of scientific results and the use of more meaningful clinical outcomes are both needed to effectively translate research into clinical practice.