Affective phases developing in personality disorder (index-sample--98 patients) were compared to those in cyclothymia (85 patients--control group). A preference of phase dynamics in the group of abnormalities relating to ICD-10 item "Borderline personality disorder" was confirmed. In line with a concept considering personality disorders as clinical syndromes, patients of the index-group have personality disorders with the signs of psychopathological diathesis determined by vulnerability to affective disorders. Affective phases are interpreted not only as an expression of a specific type of personality disorders dynamics but as an emergence of affective pathology, which is alternative to endogenous one both by modus of constitutional predisposition and clinical parameters (egosyntonic moderating of the phase, domination of negative affectivity in its structure, amphitymic duality of pathologically altered affect).