Background: Although the association between childhood parental loss and later development of mood disorder has received much research interest in the past, the results obtained and conclusions drawn have been various, and inconsistent with each other. The present study aims to examine this old, yet unresolved, question among the Japanese.
Methods: Patients with bipolar disorder (n = 73) and unipolar depression (n = 570) and community healthy controls (n = 122) were examined as to their psychopathology and childhood parental loss experiences with semi-structured interviews.
Results: Stratified for sex and age, no statistically significant difference was observed in the incidence of paternal or maternal death or separation before age 16 between bipolar patients and healthy controls. Female patients with unipolar depression under the age of 54 experienced significantly more maternal loss than the corresponding controls. This excess in loss appeared to be largely due to the patients experiencing separation from their mothers.
Conclusion: Our findings concerning bipolar disorder have replicated the previous two studies reported in the literature. Those concerning unipolar depression appear to be in line with several recent studies on the subject but, as stated, many discrepant findings can also be found in the literature.