Children of Bipolar Parents Are At Risk for Depression and Bipolar Disorder
The Pittsburgh Bipolar Offspring study, led by Boris Birmaher of the University of Pittsburgh, investigated risk of illness in the offspring of parents with bipolar disorder. The study included 233 parents with bipolar disorder and 143 controls. In addition to bipolar disorder, parents in the study had many other disorders, including anxiety (70%), panic (40%), a disruptive behavior disorder (35%), attention-deficit hyperactivity disorder or ADHD (25%), and substance use disorder (35%).
The offspring averaged age 12 at entry in the study. Offspring of parents with bipolar disorder had more illness than those of control parents, including bipolar spectrum disorders (10.6% versus 0.8%), depression (10.6% versus 3.6%), anxiety disorder (25.8% versus 10.8%), oppositional defiant disorder or conduct disorder (19.1% versus 8.0%), and ADHD (24.5% versus 6.7%). Of these differences, only bipolar spectrum disorders and anxiety were statistically significant after correcting for differences in the parents’ other diagnoses.
Two factors predicted bipolar spectrum disorders in the offspring: younger age of a parent at birth of child and bipolar disorder in both parents. Older children and those with diagnoses of anxiety or oppositional defiant disorder were more likely to be diagnosed with bipolar disorder.
On long-term follow-up that continued on average until the offspring reached age 20, 23% of those participants who had a parent with bipolar disorder developed any type of bipolar disorder, versus only 1.2% of the children of controls. Of these 23%, about two-thirds had a depressive episode prior to the onset of their bipolar disorder.
Of the offspring of parents with bipolar disorder who developed a bipolar spectrum illness, 12.3% developed bipolar I or II disorders, while 10.7% were diagnosed with bipolar not otherwise specified (NOS). Of those with bipolar NOS, which some consider to be sub-threshold bipolar disorder, about 45% converted to a bipolar I or II diagnosis after several years of prospective follow-up. These data, along with the finding that children with bipolar NOS are highly impaired and take more than a year on average to remit, stress the importance of vigorously treating this subtype, even if it does not meet the full threshold for bipolar I or bipolar II.
Birmaher indicated that although about 50% of the offspring of a bipolar patient had no diagnosis, the high incidence of multiple psychiatric difficulties developing over childhood and adolescence spoke to the importance of attempts at early intervention and prevention. Studies of effective treatment and prevention strategies are desperately needed. So far only family focused therapy (FFT), an intervention developed by researcher David Miklowitz, has shown significant benefits over standard treatment in children with a positive family history of bipolar disorder who already have a diagnosis of anxiety, depression, or bipolar not otherwise specified.