A closer look at depression in mothers who kill their children: is it unipolar or bipolar depression?

OBJECTIVE The purpose of this retrospective study was to investigate the prevalence of bipolar depression and differentiate the factors that could predict bipolar disorder among filicidal depressive mothers. METHOD Among the offenders who were sentenced to undergo treatment at the National Institute of Forensic Psychiatry, Gongju, Korea, for committing filicide or attempting filicide during 1987 to 2006, 45 women were selected whose final diagnoses at discharge were major depressive disorder or bipolar disorder based on DSM-III-R and DSM-IV criteria. Retrospective medical chart review was performed, mainly focusing on the prevalence rate of bipolar depression, including the rate of diagnostic change during admission. We also investigated the characteristic symptoms of depressive episodes that could predict bipolar disorder. RESULTS At admission, in only 24.4% of the patients (N = 11) was bipolar disorder diagnosed. However, on the basis of diagnosis at discharge, a bipolar disorder prevalence rate of 73.3% (N = 33) was found. Of the patients with major depressive disorder at admission, 64.7% (N = 22) were subsequently reclassified as having bipolar disorder based on newly observed hypomanic or manic episodes during the admission period. The significant (p < .05) depressive symptoms at the time of filicide that could predict bipolar depression were the presence of postpartum-onset depression (95% CI = 1.45 to 160.88), psychotic symptoms (95% CI = 1.94 to 215.81), and nonaltruistic motivation for filicide (95% CI = 1.68 to 133.36). CONCLUSION Our results suggest that mental health professionals should consider the possibility of bipolarity when they examine filicidal depressive mothers with postpartum-onset depression, psychotic symptoms, and nonaltruistic motivation for filicide.