Familial aggregation of postpartum mood symptoms in bipolar disorder pedigrees

Payne JL, MacKinnon DF, Mondimore FM, McInnis MG, Schweizer B,Zamoiski RB, McMahon FJ, Nurnberger Jr JI, Rice JP, Scheftner W,Coryell W, Berrettini WH, Kelsoe JR, Byerley W, Gershon ES,DePaulo Jr JR, Potash JB. Familial aggregation of postpartum moodsymptoms in bipolar disorder pedigrees.Bipolar Disord 2008: 10: 38–44. a Blackwell Munksgaard, 2008Objectives: We sought to determine if postpartum mood symptomsand depressive episodes exhibit familial aggregation in bipolar Ipedigrees.Methods: A total of 1,130 women were interviewed with the DiagnosticInterview for Genetic Studies as part of the National Institute of MentalHealth (NIMH) Genetics Initiative Bipolar Disorder CollaborativeStudy and were asked whether they had ever experienced moodsymptoms within four weeks postpartum. Women were also askedwhether either of two major depressive episodes described in detailoccurred postpartum. We examined the odds of postpartum moodsymptoms in female siblings, who had previously been pregnant and hada diagnosis of bipolar I, bipolar II, or schizoaffective (bipolar type)disorders (n ¼ 303), given one or more relatives with postpartum moodsymptoms.Results: The odds ratio for familial aggregation of postpartum moodsymptoms was 2.31 (p ¼ 0.011) in an Any Mood Symptoms analysis(n ¼ 304) and increased to 2.71 (p ¼ 0.005) when manic symptoms wereexcluded, though this was not significantly different from the Any MoodSymptoms analysis. We also examined familial aggregation ofpostpartum major depressive episodes; however, the number of subjectswas small.Conclusions: Limitations of the study include the retrospectiveinterview, the fact that the data were collected for other purposes and theinability to control for such factors as medication use. Taken togetherwith previous studies, these data provide support for the hypothesis thatthere may be a genetic basis for the trait of postpartum mood symptomsgenerally and postpartum depressive symptoms in particular in womenwith bipolar disorder. Genetic linkage and association studiesincorporating this trait are warranted.