[Psychiatric diagnosis and nosological theory: studies on the individual diagnostic schema of the physician].

This study is concerned with the diagnostic process of psychiatrists. Two concepts are investigated; the internalized nosological theory and the psychiatric diagnostic scheme. If patients or diseases are judged on predefined lists of symptoms (e.g. AMDP-list), we assume that judgments are based on the first one. If the psychiatrist, however, is free in the choice of relevant attributes in judging patients or diseases, we assume that his judgments are based on his individual diagnostic scheme. Results show high agreement in internalized nosological theories, but strong individual differences in diagnostic schemes. Interindividual agreement in internalized nosological theories is still greater than intraindividual agreement between diagnostic scheme and nosological theory. This proves that distinguishing the two concepts is meaningful. Structural components of both concepts, e.g., their dimensions, pregnant structures, and their metric, were analyzed by multidimensional scaling. We assume that the psychiatric diagnostic scheme determines the clinical diagnosis in everyday practice, whereas the internalized nosological theory is of importance mainly in research. The differences between both concepts suggest that lists of symptoms are not very helpful in analyzing clinical diagnosis. Thus, in order to achieve greater agreement in diagnosis, further and detailed analysis of individual "implicit" theories which determine the greater part of diagnostic schemes is necessary.