Childhood mental health difficulties mediate the long‐term association between early‐life adversity at age 3 and poorer cognitive functioning at ages 11 and 14

Early-life adversity is associated with adverse mental health outcomes and poorer cognitive functioning in later development. However, little is known about how early-life adversity, mental health, and cognition affect one another or how the effects unfold over time. Here, we test the hypothesis that early-life adversity may lead to mental health challenges which in turn have adverse consequences for the development of cognitive abilities.In a large (N = 13,287) longitudinal (5 wave) sample assessed at ages 3, 5, 7, 11 and 14, we use both path analysis approach and latent growth curve mediation model to study whether poorer mental health in childhood may mediate the effects of early-life adversity on later working memory and vocabulary outcomes.We found a significant total association between early-life adversity and poorer performance on working memory (β = .123, p < .001, [95% CI 0.106, 0.141]) and vocabulary scores (β = -.111, p < .001, [95% CI -0.129, -0.093]). Notably, current and previous mental health mediated a substantial proportion (working memory: 59%; vocabulary: 70%) of these effects. Further longitudinal modeling showed that early-life adversity has an enduring adverse effect on mental health, and that poorer mental health is associated with poorer cognitive performance later on in development. In a complementary analysis using latent growth curve mediation model, we found indirect associations between early-life adversity and working memory through baseline mental health at age 3 (intercept: β = .083, p < .001, [95% CI 0.072, 0.094]) and change in mental health across ages 3-11 (slope: β = -.012, p = .001, [95% CI -0.019, -0.005]). Likewise, baseline mental health at age 3 (intercept: β = -.095, p < .001, [95% CI -0.107, -0.083]) and change in mental health across ages 3-14 (slope: β = .007, p = .001, [95% CI 0.003, 0.011]) significantly and completely mediated the relation between early-life adversity and vocabulary outcome.These findings have important potential clinical and educational implications, because they suggest that academic and cognitive resilience may be supported through early mental health interventions in vulnerable children.