[General methodological problems of psychotropic drug trials (author's transl)].

The difference between the methodological approach of the basic neuro-sciences and the descriptive clinical methods consists in the possibility of isolating the object studied in the former, and in the complexity of relevant clinical terms in the latter which can only be quantified secondarily. Psychopathological symptoms, even operationalized and quantified as items in rating scales, remain complex, whereas the values taken from the substratum, i.e. physiological or biochemical can clearly be evaluated. The complexity of measuring psychopathological symptoms is illustrated in a study in which the scores of different scales of depressive patients are correlated before and after treatment, and the step from the physiological to the psychological level is discussed by means of the results of a psychophysiological study with normal subjects who were given a sedative. These results suggest a heterogeneity of samples of psychiatric patients selected for therapeutic studies according only to clinical criteria. This heterogeneity is discussed on five levels of psychopathological states in depressive, schizophrenic and nonpsychotic anxiety syndromes. Particular interest is put on to the psychophysiological level. From this heterogeneity of samples of psychopharmacological studies, two conclusions can be drawn: 1) Double blind studies are of limited value, since so far only the general effects of whole categories of psychotropic drugs could be determined, whereas it was not possible to determine specific indications for an individual drug. 2) The object of research must be to embody psychopathological states in psychophysiological and clinical-biochemical data, in order to find more homogeneous subgroups of psychiatric patients and to optimize therapeutic procedures; in other words, to find out which patients respond best to a given drug. This strategy, however, limits the generalisation of therapeutic use of a given drug, but it permits to find more specific indications. This is, of course, a general principle in the development of psychiatric therapy.