Social and Cognitive Functioning as Risk Factors for Suicide: A Historical-Prospective Cohort Study

ObjectivesPrevious studies have shown that poor cognitive and social functioning are associated with increased risk of suicide. This study aimed to examine the association between social and cognitive functioning in adolescence and later completed suicide. DesignHistorical prospective cohort study Setting and ParticipantsData from the Israeli Draft Board Register for 756,223 Israeli male adolescents aged 16-17 was linked to a causes-of-death data registry, enabling up to 20 year follow-up (mean 10.4 year) for completed suicide (N=993). ResultsPoorer cognitive and social functioning were both associated with increased risk of later suicide (adjusted HR=1.44, 95% CI: 1.18-1.76 and adjusted HR=2.3, 95% CI: 1.53-3.4, respectively). Regardless of their level of social functioning, adolescents who scored one point or more below their siblings on the social functioning scale had increased risk of later suicide (adjusted HR=1.41, 95% CI: 1.09-1.82).ConclusionsIn adolescent males, poor cognitive and social abilities are associated with a slightly increased risk of later suicide. Male adolescents who function poorly compared to their brothers are also at increased risk for later suicide. These data underscore the importance of cognition and social abilities in understanding the phenomenon of suicide, and particularly indicate the significance of sibling rivalry in the etiology of suicide. However, because suicide is a rare event and poorer cognitive and social function in the general population is very prevalent, these characteristics are not useful as clinical predictors of suicide.