Fifty manic probands were examined for age at first onset of affective illness, subsequent clinical course, any associated alcoholism, drug abuse, sociopathy or homosexuality. Information was obtained for all first-degree relatives for history and type of affective illness.
Onset of affective illness before age 30 was associated with a bipolar illness course, equal number of prior attacks of mania and depression, and a high prevalence of affective disorder, alcoholism, drug abuse, and sociopathy in first-degree relatives. Onset of affective illness after age 30 was associated with a unipolar manic course, excess prior attacks of mania, and a dearth of affective illness and associated conditions in first-degree relatives.
These data suggest that mania is not a single clinical entity and should not be used as the sole criterion for the diagnosis of bipolar illness.
Taylor M, Abrams R. Manic StatesA Genetic Study of Early and Late Onset Affective Disorders. Arch Gen Psychiatry. 1973;28(5):656-658. doi:10.1001/archpsyc.1973.01750350036007