[Psychiatry and interdisciplinary research. Value of a systems approach]

Interdisciplinary research is particularly difficult, because of the different frames of reference used in the individual disciplines. Psychiatry by itself show already the complexity of the current methodological situation. A fundamental epistemological problem is posed by the unity and uniqueness of the patient as opposed to the multiple-faceted traits and experiences presented to the observer. The authors show the utility of the systems concept for solution of these difficulties. They depict the characteristics of "the systemal method", the way it is employed and its many applications in the clinic as well as in pharmacology, neurochemistry, neurophysiology and ethology. The systemal approach allows comparison and integration of data and results from various disciplines by means of the concepts "homology" and "isomorphism", and may thus contribute to progress in the study of biological psychiatry. It also makes it possible to regard the organism as an ensemble of sub-systems in interaction with its environment. Finally, because of its logicomathematical foundation, the systemal approach lends itself readily to application of computer techniques.