Familiality of the puerperal trigger in bipolar disorder: Results of a family study

Objective: Puerperal psychosis, an episode of mania or psychosis precipitat ed by childbirth, follows approximately one in 1,000 deliveries. The eviden ce of clinical, outcome, and genetic studies supports the hypothesis that t he majority of puerperal psychotic episodes are manifestations of an affect ive disorder diathesis with a puerperal trigger. Family studies of puerpera l psychosis consistently demonstrate familiar aggregation of psychiatric (p articularly affective) disorder and suggest a major overlap in the familial factors predisposing to puerperal psychosis and bipolar disorder. The sing le large study that used direct interview of relatives suggested that famil ial factors play a role in vulnerability to puerperal triggering itself. Th e authors' goal was to test this hypothesis further Method: They conducted a study of the occurrence of episodes of puerperal p sychosis in families multiply affected with bipolar disorder participating in an ongoing molecular genetic study of bipolar disorder in sibling pairs. Results: Episodes of puerperal psychosis followed 81 (26%) of 313 deliverie s to 152 parous women with bipolar disorder, 58 (38%) of whom had at least one puerperal psychotic episode. Puerperal episodes clustered in families. Episodes of puerperal psychosis occurred in 74% (N=20) of the 27 parous wom en with bipolar disorder who had a family history of puerperal psychosis in a first-degree relative but in only 30% (N=38) of the 125 women with bipol ar disorder with no such family history. Conclusions: These results conclusively demonstrate that familial (probably genetic) factors are implicated in susceptibility to triggering of puerper al episodes in women with bipolar disorder. These findings have implication s for future research and will be of use clinically in the management of wo men with bipolar disorder who are considering pregnancy.