State-level social capital and suicide mortality in the 50 U.S. states.

This study investigated whether state levels of social capital are associated with rates of completed suicides in the fifty U.S. states. To do this we regressed state-level suicide rates on an index of social capital, along with other variables known to influence suicide rates such as gun ownership, income inequality, alcohol abuse and dependence, drug abuse and dependence, serious mental illness, unemployment, percent of population living in urban areas, poverty, population instability, and living in a "suicide belt" state. Suicide rates were aggregated from 1999 to 2002, and examined separately by sex and different race/ethnic groups. The results showed that White men and women in states with higher levels of social capital had significantly lower rates of suicide when controlling for the other influential variables. When we examined sub-dimensions of social capital, we found that community organizations (for White women) and group membership (for White men) were particularly strongly associated with lower suicide risk.