Parental death and bipolar disorder: a robust association was found in early maternal suicide.
BACKGROUND
Previous studies have suggested that early parental death may be associated with the emergence of bipolar disorder in later life. However, it remains unknown whether this association applies specifically to parental death due to suicide or only to early parental death. The present study aimed to explore whether suicide as well as the non-suicidal death of father, mother, or siblings are associated with an increased risk for bipolar disorder, and whether the possible association is modified by the age at which the subject experiences such a death in the family.


METHODS
The subjects were born in 1960 or later and were first admitted to or had first contact with Danish psychiatric facilities between 1981 and 1998 with a diagnosis of bipolar disorder, and fifty age-matched controls per case were extracted. The effects of the deaths of relatives were estimated by means of a conditional logistic regression analysis.


RESULTS
Among 947 subjects with bipolar disorder and 47,350 controls, those having experienced the parental suicide were significantly associated with an increased risk for BPD (incidence rate ratios: 1.83 [95% confidence interval: 1.07 to 3.12] for paternal suicide, 3.44 [1.97 to 6.00] for maternal suicide), whereas the non-suicidal death of parents showed no such association. Those having experienced maternal suicide at some point before reaching 10 years of age were seven times as likely to develop bipolar disorder.


CONCLUSIONS
The cohort members were followed until, but not exceeding, the age of 38.


CONCLUSIONS
Early parental, particularly maternal, suicide increases the risk for bipolar disorder in the offspring. Possible explanations include a family history of mental disorders as well as psychosocial factors.
Tsuchiya
Kenji J
KJ
Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Handayama 1, Hamamatsu 4313192, Japan. tsuchiya@zah.att.ne.jp
Agerbo
Esben
E
Mortensen
Preben B
PB
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001601:Bereavement; D001714:Bipolar Disorder / Q000453:epidemiology* / Q000209:etiology / Q000523:psychology; D016022:Case-Control Studies; D002423:Cause of Death; D002648:Child; D016241:Child of Impaired Parents; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005220:Fathers / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D009035:Mothers / Q000706:statistics & numerical data; D010290:Parents; D012307:Risk Factors; D035781:Siblings; D013405:Suicide / Q000523:psychology* / Q000706:statistics & numerical data