Types of Depressive Illness

A major problem in the affective disorders is what constitutes an homogeneous illness. A recent study enabled us to separate depressive illnesses into two types (1). The first we have called ‘depression spectrum disease’; its prototype is a female with an onset of a depressive illness before the age of 40, in whose family more depression is seen in female relatives than in male relatives, the deficit in males being made up by alcoholism and sociopathy. The second illness we have called ‘pure depressive disease’, the prototype of which is a male whose depression starts after age 40 and in whom there are equal amounts of depression in both male and female relatives and no large amount of alcoholism or sociopathy in the males. First degree relatives of depression spectrum disease are more likely to be psychiatrically ill (depression, sociopathy or alcoholism) than first degree relatives of pure depressive disease probands. Data of Hopkinson and Ley support this concept in part (2); they found that early-onset affective probands (< 40) had higher morbid risks for affective illness in relatives than late-onset probands (onset after 40). Further confirmation comes from a study of 259 alcoholics and their first degree relatives (3). Most of the psychiatrically ill male relatives had alcoholism; most of the psychiatrically ill female relatives had depression. As of the present the differentiation of the two kinds of depressive illness is made on the basis of a specific familial predisposition. Major clinical differences in the two groups have eluded us.