The measurement of change in endogenous affective disorders.

Psychopathological syndromes, as originally revealed by clinical observation, can also be detected by multivariate statistical analyses of symptom ratings. Changes in the course of psychiatric syndromes may be rated simply by improvement scales or by consecutive quantifications of symptoms and their comparison in chronological order. For the latter approach, which is less liable to bias, clinical ratings of psychopathology by staff members, self-ratings by the patients, analyses of patients' overt behavior (including video and speech records), or objective measurements of psychological and/or physiological variables can be used. Advantages and limitations of these different methods are discussed and illustrated by examples from ongoing clinical research in affective disorders. Generally, the combined use of different rating procedures is recommended. Self-ratings are economical, but they may represent aspects of psychopathology other than clinical ratings. In endogenous depression, mood scales are valid (supplementary) tools for the quantification of long-term as well as short-term changes, including diurnal variations. In severe conditions of mania, however, clinical rating has been--until now--the only valid basis for quantifying the degree of psychopathology and its changes with time. Precise evaluation of changes in psychopathology is essential in longitudinal investigations of endogenous affective disorders, since psychopathology up to now seems to have been the most sensitive and the most specific indicator of the hypothetical underlying abnormalities of cerebral functioning.