Objective: To investigate the type and distribution of psychiatric disorders in the child and adolescent members of extended pedigrees identified through bipolar probands.
Method: The child and adolescent offspring (24 male, 26 female, aged 6 to 17 years) and the adult parents (60) of 14 bipolar pedigrees ascertained for the National Institutes of Mental Health Genetics Initiative Study of Bipolar Affective Disorder were personally assessed using structured psychiatric interviews. A parent was also interviewed about each child or adolescent offspring.
Results: Twelve of the 50 interviewed offspring received a lifetime DSM-III-R diagnosis of an affective disorder. This included six cases of bipolar disorder, five cases of major depressive disorder, and one case of dysthymia. Eight of the offspring who received an affective disorder diagnosis also qualified for an anxiety disorder (four), a disruptive behavior disorder (two), or both (two). Offspring who had a parent with an affective disorder had a 5.1-fold higher risk for receiving an affective disorder diagnosis than did offspring with healthy parents.
Conclusions: In a consecutive series of families identified through a proband with bipolar disorder, there were significant increases in the prevalence of affective disorder diagnoses in the child and adolescent offspring. The distribution of illness in offspring was compatible with the presence of important genetic factors which contribute to early-onset affective illness.