Children's cognitive performance and suicide risk through middle adulthood

Longitudinal studies show that lower cognitive performance in adolescence and early adulthood is associated with higher risk of suicide death throughout adulthood. However, it is unclear whether this cognitive vulnerability originates earlier in childhood since studies conducted in children are scarce and have inconsistent results.

Vital status of 49,853 individuals born between 1959 and 1966 to participants in the Collaborative Perinatal Project cohort was determined by a probabilistic linkage to the National Death Index, covering all US deaths occurring from 1979 through 2016. Cox proportional hazard models were used to examine associations of general, verbal, and non-verbal intelligence at ages 4 and 7, and academic skills at age 7 with suicide death coded according to ICD-9/10 criteria, while accounting for sociodemographic and pregnancy factors previously associated with suicide in this sample.

By the end of 2016, 288 cohort members had died by suicide. Cognitive performance at 7 years on tests with verbal components was associated with suicide risk (average vs. high verbal intelligence, HR = 1.97, 95% CI 1.05-3.71; low vs. high spelling skills, HR = 2.02, 95% CI 1.16-3.51; low vs. high reading skills, HR = 2.01, 95% CI 1.27-3.17). Associations were still evident, especially for verbal intelligence and reading skills, but hazard ratios were attenuated after adjusting for prenatal and sociodemographic factors at birth (verbal intelligence, HR = 1.97, 95% CI 1.03-3.78; spelling, HR = 1.61, 95% CI 0.90-2.88; reading, HR = 1.67, 95% CI 1.02-2.72).

Childhood neurocognitive performance is associated with vulnerability to suicide mortality through middle-adulthood, suggesting that there might be a cognitive diathesis for suicide originating in early childhood. Future studies should examine how multiple domains of childhood cognitive performance contribute to vulnerability to suicide risk, including by increasing risk for social and environmental factors that are associated not only with suicide but also with many types of psychiatric disorders.