A family history study of twenty probands with childhood manic-depressive illness.

Abstract A family history study was conducted on first and second degree relatives of 20 probands diagnosed with childhood manic depression. Overall rates of unipolar and bipolar illness were 27 and 14%, respectively. Of probands' parents, 62.5% were positive for major affective disorder. No significant differences were found between male and female relatives for major affective disorders. The mean age of onset for major depression and manic depression among family members was 23.5 and 19.5, respectively. High rates of observed psychopathology and the early age of onset among family members strengthen the concept that manic depression in childhood represents the same biological entity recognized in adulthood and that early onset, as seen in our probands, may suggest a more severe form of the disorder.