Anankastic traits were sought in a group of 100 consecutive inpatients, over the age of 50, diagnosed as suffering from affective psychosis. Such traits were common and were not significantly more frequent in those patients who suffered an initial attack over the age of 50. Anankasm amounting to psychopathy was less common but affected both early and late onset cases approximately equally. The pathoplastic effect of anankasm in this group of patients was confined to the presence of compulsive features in the clinical picture. The relationship between anankasm and affective illness is discussed in the light of these findings.