Multigenerational transmission of liability to psychiatric illness in offspring of parents with bipolar disorder.

A family history of illness burden in prior generations was previously related to an earlier age of onset of bipolar illness in our adult patients with bipolar disorder and is now also found to be related to the incidence of multiple psychiatric illnesses in their offspring. Genetic and epigenetic mechanisms deserve consideration for this multigenerational conveyance of illness vulnerability, and clinical and public health attempts to prevent or slow this transmission are indicated.