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January 1991

Suicide in Twins

Author Affiliations

From Hillside Hospital, a Division of Long Island Jewish Medical Center (Dr Roy); the Minnesota Center for Twin and Adoption Research, University of Minnesota, Minneapolis (Dr Segal); the Departments of Psychiatry and Epidemiology, University of Washington, Seattle (Dr Centerwall); and the Medical Follow-up Agency, National Academy of Sciences—National Research Council, Washington, DC (Dr Robinette).

Arch Gen Psychiatry. 1991;48(1):29-32. doi:10.1001/archpsyc.1991.01810250031003

• Suicide appears to cluster in fanmilies, suggesting that genetic factors may play a role in this behavior. We studied 176 twin pairs in which one or both twins had committed suicide. Seven of the 62 monozygotic twin pairs were concordant for suicide compared with two of the 114 dizygotic twin pairs (11.3% vs 1.8%). The presence of psychiatric disorder in the twins and their families was examined in a subsample of 11 twin pairs, two of whom were concordant for suicide. Eleven of these 13 twin suicide victims had been treated for psychiatric disorder, as had eight of their nine surviving cotwins. In addition, twins in 10 pairs had other first- or second-degree relatives who had been treated for psychiatric disorder. Thus, these twin data suggest that genetic factors related to suicide may largely represent a genetic predisposition for the psychiatric disorders associated with suicide. However, they leave open the question of whether there may be an independent genetic component for suicide.