Vol. 10, No. 1, 2004 Page 4
Family members of suicide victims are at higher-than- average risk of attempting suicide themselves. A new study by D. A. Brent and colleagues indicates that genes contribute powerfully to this risk.
The researchers compared the offspring of three groups of people suffering from mood disorders:
Brent et all report that the offspring of the first group (in which both the parent and a sibling of the parent had attempted suicide) had a higher risk of attempting suicide than did offspring of a non-suicidal parent, and had an earlier age of onset of suicidal behavior than the offspring of a suicidal parent with a non-suicidal sibling. In addition, they found, subjects with suicidal siblings, and their offspring as well, reported greater levels of lifetime impulsive aggression when compared with the other two groups. For the offspring, impulsive aggression proved to be the most powerful predictor of suicide attempts made early in life.
The researchers conclude, "Familial loading for suicide attempts may affect rates of transmission as well as age at onset of suicidal behavior, and its effect may be mediated by the familial transmission of impulsive aggression."
Commenting on the study in the Psychiatric Times, Ping Qin notes that the tendency of suicidal behavior to run in families is most likely due to genetic factors. Qin notes that identical twin pairs have a significantly greater concordance for both completed and attempted suicide than fraternal twin pairs, and cites a study showing that suicide is more common among biological relatives of adopted suicides than among biological relatives of adopted non- suidical controls. Qin's own study showed that suicide mortality in first-degree relatives of suicide victims is 3.5 times higher than in first-degree relatives of controls.
"Peripubertal suicide attempts in offspring of suicide attempters with siblings concordant for suicidal behavior," D. A. Brent, M. Oquendo, B. Birmaher, L. Greenhill, D. Kolko, B. Stanley, J. Zelazny, B. Brodsky, S. Firinciogullari, S. P. Ellis, and J. J. Mann, American Journal of Psychiatry, Vol. 160, No. 8, August 2003, 1486-93. Address: D. A. Brent, Western Psychiatric Institute and Clinic, Pittsburgh, PA 15213.
"The relationship of suicide risk to family history of suicide and psychiatric disorders," Ping Qin, Psychiatric Times, Vol. 20, No. 13, December 2003. Address: Ping Qin, National Centre for Register-Based Research, Aarahus University, Denmark.