"Involution melancholia," sometimes spoken of simply as "melancholia," is one of the most frequent forms of mental disease, and the term is one of the oldest in psychiatry. Nevertheless, the clinical position of this group and the outcome of the psychosis are still matters of dispute. Until 1907 the disease was generally held to be a clinical entity with variable prognosis. For instance, in the seventh edition of his textbook, Kraepelin says: "It includes all pathological states of anxiety in more advanced age, which are not episodes in the course of other forms of insanity. Delusions belong also to this clinical picture in addition to the mood disturbances." As to the prognosis, he found that 32 per cent, of his cases were chronic, while 19 per cent, of his patients died within two years after the onset.
Only one important objection was made to the view that involution melancholia is