Objective: To examine childhood problem behaviors manifested as externalizing behaviors (e.g., aggression, impulsivity) and internalizing behaviors (e.g., anxiousness, avoidant behavior) as predictors of mortality by the age of 46 years and to assess whether these associations are dependent on childhood family background.
Method: The participants were 5,426 girls and 5,716 boys born in 1958 and participants in the British National Child Development Study (total N = 11,142). Childhood problem behaviors were assessed by teachers at ages 7 and 11 years, and the participants were followed for mortality to the age of 46 years.
Results: Both externalizing and internalizing behaviors were associated with mortality in adulthood. By the age of 46 years, the cumulative probabilities of death by increasing externalizing score quartiles were 1.4%, 2.2%, 2.3%, and 3.2%, respectively (odds ratio [OR] for mortality per 1 SD increase in standardized externalizing score 1.27; 95% confidence interval [CI] 1.13-1.44). The corresponding percentages for internalizing score quartiles were 1.8%, 1.9%, 2.3%, and 3.0% (OR 1.20; 95% CI 1.06-1.35). Adjusting for father's social class, family difficulties, family size, and cognitive ability attenuated these associations for externalizing behaviors (OR 1.21; 95% CI 1.06-1.37) and for internalizing behaviors (OR 1.11; 95% CI 0.98-1.26). Childhood environment did not modify the association between problem behaviors and mortality.
Conclusions: Childhood problem behaviors are associated with increased long-term mortality risk beyond childhood and adolescence.