What Role Does Genetics or Family History Play in Bipolar Disorder?

Discover how genetics and environmental factors can influence whether a child will develop bipolar disorder.

Genetics Play Significant Role in Development of Bipolar Disorder in Children

The illness tends to be highly genetic, but there are clearly environmental factors that influence whether the illness will occur in a particular child. Bipolar disorder can skip generations and take different forms in different individuals.

The small group of studies that have been done vary in the estimate of risk to a given individual:

• For the general population, a conservative estimate of an individual's risk of having full-blown bipolar disorder is 1 percent. Disorders in the bipolar spectrum may affect 4-6%.
• When one parent has bipolar disorder, the risk to each child is l5-30%.
• When both parents have bipolar disorder, the risk increases to 50-75%.
• The risk in siblings and fraternal twins is 15-25%.
• The risk in identical twins is approximately 70%.

In every generation since World War II, there is a higher incidence and an earlier age of onset of bipolar disorder and depression. On average, children with bipolar disorder experience their first episode of illness 10 years earlier than their parents' generation did. The reason for this is unknown.

The family trees of many children who develop early-onset bipolar disorder include individuals who suffered from substance abuse and/or mood disorders (often undiagnosed). Also among their relatives are found highly-accomplished, creative, and extremely successful individuals in business, politics, and the arts.

next: Scientists Close in on Multiple Gene Sites for Bipolar Disorder
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