Leo Sher, M.D.

A research paper, “Geographic proximity is associated with transmission of suicidal behavior among siblings” has been published in Acta Psychiatrica Scandinavica online ahead of print (1). The authors examined the role of “contagion”, or social transmission, in the risk of suicidal behavior among siblings. They employed Swedish national registry data to empirically study the role of contagion in risk of suicidal behavior in siblings, using proximity of residence between siblings as a proxy for exposure.

Researchers followed Swedish sibling pairs until one of the siblings was registered for a non-lethal suicide attempt or suicide death. 111,848 siblings were registered after suicidal acts. Within three years after the suicidal act of the first sibling, 1,112 (1.0%) second siblings were registered for suicidal behavior (998 non-lethal suicide attempts and 114 suicide death). The authors found that people who lived closer to a sibling who had attempted or completed suicide were at greater risk for later suicidal behavior. Hazard ratios declined rapidly up to 25 km and mostly became stable beyond 150 km. The influence of geographic proximity to a sibling’s suicidal behavior was not different between individuals under 25 years of age versus those 25 years of age or older.

The authors concluded that consistent with the concept of suicide contagion, risk of suicidal behavior subsequent to a sibling’s suicide death or non-lethal attempt is higher as a function of sibling closeness. This study suggests that exposure to a suicidal act is an independent suicide risk factor.

References

1. Edwards AC, Ohlsson H, Mościcki EK, Sundquist J, Sundquist K, Kendler KS. Geographic proximity is associated with transmission of suicidal behavior among siblings. Acta Psychiatr Scand. 2019 May 18. doi: 10.1111/acps.13040. [Epub ahead of print]