The "dark side" of the strength of weak ties: the diffusion of suicidal thoughts.

Granovetter's theory on the strength of weak ties motivates hypotheses on the difusive nature of suicidal thoughts in the friendship networks of adolescents. Using data from the National Longitudinal Study of Adolescent Health, the effects of friends-of-friends attempting suicide on the suicidal thoughts of respondents are estimated. A focus on friends-of-friends permits a test of the weak-ties thesis because respondents are indirectly linked to friends-of-friends by "open ties" that are both structurally weak and used as bridges. Results for "at-risk" respondents--or those with certain behaviors, statuses, and experiences that create psychological predispositions to suicide-are consistent with Granovetter's theory and thus reveal the "dark side" of the strength of weak ties as at-risk respondents are more likely to seriously think about committing suicide when a friend-of-a-friend attempts suicide, controlling for past suicidal thoughts by the respondent and attempts by friends, family, and students in the respondent's school, among other control factors. Barriers to diffusion are also considered.