[The method of joined multi-center studies in clinical psychopharmacology]

Joined multicentered studies are of interest more and more growing up in the field of clinical psychopharmacology. Only such studies should be carried out which have a high scientific value to avoid unnecessary waste. According to this fact the preconditions are greater than such required for a single-center study. Also long-term studies require more preconditions than short-term studies. Pilot studies with clinically more or less unknown drugs should be avoided in multicentered studies for the same reasons. Of great importance is the selection of subjects. The single centers should have well comparable groups of patients. Nevertheless the number of selection criterias should be as few as possible, because also with only some few simple criterias the total number of patients is greatly restricted. The most likely group would consist of patients with acut diseases either recently admitted to the hospital or outpatients who conform to some good defined criterias. Of great importance is the control group. Ethical problems are playing an important role in this field. In view of the fact that the precise action mechanism of drugs is unknown at present, the randomization method will appear to be the best available selection method at the moment. The cross-over-method in mentally ill patients seems hardly suitable out of diverse reasons. Considering the dosage it seems that a limited and fixed dosage is a practicable compromise. Of greatest importance naturally is the good documentation and quantification of the results. Rating-Scales therefore are more suitable than check-lists. Some well introduced and validated rating-scales are existing and mentioned. As important instruments as the rating-scales are the self-rating-scales. Furthermore of great interest in such studies can be the multicentered additional measuring of some psychophysiological variables, for example with the polygraph.