Year: 2006 Source: American Journal of Psychiatry, v.163, no.2, (February 2006), p.240-246 SIEC No: 20080868

A total of 211 families with 1856 subjects were ascertained through bipolar I disorder probands. Admixture analysis was used to decompose the age-at-onset distribution into a mixture of theoretical normal distributions. Logistic regression with general estimating equations was then used to examine clinical correlates & familial aggregations of age at onset in all 717 bipolar disorder subjects. Early-onset (age at onset, 21 years or less) subjects had higher risks of drug abuse, alcohol abuse, rapid cycling, & suicide attempts. Findings are consistent with the conclusion that age at onset reflects underlying genetic heterogeneity in bipolar disorder. (34 refs.)