Suicide in Twins Alec Roy,
MB; Nancy L. Segal, PhD; Brandon S. Centerwall, MD, MPH; C. Dennis Robinette, PhD
\s=b\ 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. (Arch Gen Psychiatry. 1991 ;48:29-32)
the been renewed In suicidal possibility of genetic component associated behavior. supported by genetic recent years, there has
interest in with 1~6 A influence on suicide is data from the American/Danish adoption studies.2,4,7 Two studies reported a significantly increased incidence of suicide among biologic relatives of adopted individuals who had either com¬ mitted suicide or who had suffered from depression compared with relatives of adopted controls.4,7 In the 1940s, Kallman and Anastasio8 and Kallman et al9 encouraged the application of classic twin methods in studies of suicide: "If hereditary factors play a decisive role, we should find a concordant tendency to suicide more frequently in one-egg than in two-egg pairs." Twenty years later, Haberlandt10,11 reviewed the accumulated data in the literature on 149 sets of twins in which at least one twin committed suicide. Among these 149 twin pairs, nine sets of twins were concor¬ dant for suicide. All ofthese nine twin pairs were found among a
Apccepted for publication March 15,1990. 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\p=m-\NationalResearch Council, Washington, DC (Dr Robinette). Reprint requests to Hillside Hospital, PO Box 38, Glen Oaks, New York, NY 11004 (Dr Roy).
the 51 monozygotic (MZ) twin pairs. In contrast, concordance for suicide did not occur among the 98 dizygotic (DZ) twin pairs. This difference between MZ and DZ twins for concor¬ dance for suicide was statistically significant (Fisher's Exact
Test, P
MB; Nancy L. Segal, PhD; Brandon S. Centerwall, MD, MPH; C. Dennis Robinette, PhD
\s=b\ 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. (Arch Gen Psychiatry. 1991 ;48:29-32)
the been renewed In suicidal possibility of genetic component associated behavior. supported by genetic recent years, there has
interest in with 1~6 A influence on suicide is data from the American/Danish adoption studies.2,4,7 Two studies reported a significantly increased incidence of suicide among biologic relatives of adopted individuals who had either com¬ mitted suicide or who had suffered from depression compared with relatives of adopted controls.4,7 In the 1940s, Kallman and Anastasio8 and Kallman et al9 encouraged the application of classic twin methods in studies of suicide: "If hereditary factors play a decisive role, we should find a concordant tendency to suicide more frequently in one-egg than in two-egg pairs." Twenty years later, Haberlandt10,11 reviewed the accumulated data in the literature on 149 sets of twins in which at least one twin committed suicide. Among these 149 twin pairs, nine sets of twins were concor¬ dant for suicide. All ofthese nine twin pairs were found among a
Apccepted for publication March 15,1990. 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\p=m-\NationalResearch Council, Washington, DC (Dr Robinette). Reprint requests to Hillside Hospital, PO Box 38, Glen Oaks, New York, NY 11004 (Dr Roy).
the 51 monozygotic (MZ) twin pairs. In contrast, concordance for suicide did not occur among the 98 dizygotic (DZ) twin pairs. This difference between MZ and DZ twins for concor¬ dance for suicide was statistically significant (Fisher's Exact
Test, P
