LAUSR

Background Both biological and social mechanisms have been implicated in the transmission of suicidal behavior in younger and middle-aged adults. Yet, while suicide rates rise with age, it is not clear whether such mechanisms operate in late life. Thus, we looked for evidence of social and familial suicidal transmission in elderly with late- vs. early-onset suicidal behavior by examining exposure to suicidal behavior within biological relatives and broader social networks. Method Participants were 356 adults, aged 50 or older (mean: 67), divided into five groups: early-onset suicide attempters (first lifetime attempt before age 60), late-onset attempters, suicide ideators (without attempt history), depressed non-suicidal controls, and non-psychiatric controls. History of suicidal behavior in one’s biological relatives and friends/unrelated kin was assessed via clinical interview, and group differences were examined via generalized linear mixed-effects models. Results There was a main effect of group (χ24 = 18.38, p< 0.001) such that familial or social exposure to suicidal behavior was more prevalent in early- than late-onset attempters. Late-onset attempters’ exposure was similar to non-suicidal groups’. However, there was no significant group by relationship interaction, indicating that suicidal behavior was not significantly more prominent among the biological relatives among either attempter group. Limitations Participants’ report of exposure is subject to awareness and recall biases. Conclusion Suicidal clustering in biological relatives and friends/unrelated kin is associated with early-, but not late-onset suicidal behavior in older adults. Suicidal transmission in older adults follows a pattern of familial and social clustering suggestive of social transmission.