Evidence-based medicine in psychopharmacotherapy: possibilities, problems and limitations.

Psychopharmacotherapy should now be regulated in the sense of evidence-based medicine, as is the case in other areas of clinical treatment in medicine. In general this is a meaningful development, which principally will have a positive impact on routine health care in psychiatry. But several related problems should not be ignored. So far consensus on an internationally accepted evidence graduation could not be reached due to several difficulties related to this. For example, focussing on the results of meta-analyses instead of considering relevant single studies results in a decision-making logic which is in conflict with the rationale applied by drug authorities in the licensing process. Another example is the relevance of placebo-controlled trials: if randomized placebo-controlled phase-III studies are prioritized in the evidence grading, the evidence possibly deviates too far from the conditions of routine clinical care due to the special selection of patients in those studies. However, a grading primarily based on active comparator trials could lead to wrong conclusions about efficacy. This concerns especially the so-called "effectiveness" studies and other forms of phase-IV studies with their less restrictive methodological rigidity. Attempts to regulate psychopharmacotherapy in the sense of evidence-based medicine come closer to their limits the more complex the clinical situation and the respective decision-making logic are. Even in times of evidence-based medicine a large part of complex clinical decision-making in psychopharmacotherapy still relies more on clinical experience and a consensus on clinical experience, traditions and belief systems than on results of efficacy oriented phase-III and effectiveness-oriented phase-IV clinical studies.