[Why are guidelines more irrational than metaanalyses].
BACKGROUND
Together with a multi-professional working group, the author was responsible for the development of the German Psychiatric Association's treatment guideline on Aggressive Behaviour. Using his experience during this process, he makes some critical comments on the current methods of developing evidence-based treatment recommendations.


METHODS
Treatment recommendations derived from established levels of evidence were examined regarding their possible bias.


RESULTS
The following sources of bias were identified: 1. The levels of evidence are related to the quality of studies, not to reported effect sizes; 2. external validity of studies are not taken into account systematically; 3. absence of evidence is not evidence of absence; 4. the ethical framework of many clinically relevant objectives cannot be represented adequately in randomized controlled trials; 5. achieved consensus between professionals, users, and relatives may be highly important and receives inadequately low levels of recommendation due to the definition of evidence.


CONCLUSIONS
There is an urgent need for a clear and transparent method to get from the analysis of existing evidence to treatment recommendations.
Steinert
Tilman
T
Zentrum für Psychiatrie Weissenau, Abt. Psychiatrie I der Universität Ulm. tilman.steinert@zfp-weissenau.de
D000374:Aggression / Q000941:ethics / Q000523:psychology*; D015982:Bias; D032921:Consensus; D032984:Ethics, Research; D019317:Evidence-Based Medicine / Q000941:ethics / Q000592:standards* / Q000706:statistics & numerical data; D005858:Germany; D006801:Humans; D015201:Meta-Analysis as Topic; D010043:Outcome and Process Assessment, Health Care / Q000592:standards / Q000706:statistics & numerical data; D017410:Practice Guidelines as Topic / Q000592:standards*; D016032:Randomized Controlled Trials as Topic / Q000941:ethics / Q000592:standards / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D014754:Violence / Q000941:ethics / Q000517:prevention & control* / Q000523:psychology