Life events at the onset of primary affective illness were assessed in 183 patients with primary affective disorder who were attending a research lithium clinic. About 50% of patients recalled significant life events in the 3-month interval preceding their initial affective episode. Family history data of those patients who reported life events were not significantly different from those who did not report life events at onset. Furthermore, there were no significant differences among patients classified as bipolar or unipolar regarding reporting of life events at onset of illness. These data suggest that the delineation of a subgroup of patients with "reactive" primary affective illness is not supported by a decreased familial load for affective disorder in their relatives.