Targeted Estimation of the Relationship Between Childhood Adversity and Fluid Intelligence in a US Population Sample of Adolescents

Abstract

Many studies have shown inverse associations between childhood adversity and intelligence (IQ), though most are based on small clinical samples and fail to account for the effects of multiple co-occurring adversities. Using data from the 2001–2004 National Comorbidity Survey Adolescent Supplement, a cross-sectional US population study of adolescents ages 13–18 (n = 10,073), we examined the associations between 11 childhood adversities on IQ, using targeted maximum likelihood estimation. Targeted maximum likelihood estimation incorporates machine-learning to identify the relationships between exposures and outcomes without over-fitting, including interactions and non-linearity. The Kaufman Brief Intelligence Test nonverbal score was used as a standardized measure of fluid reasoning. Child adversities were grouped into deprivation- and threat-types based on recent conceptual models. Adjusted marginal mean differences compared the mean IQ score if all adolescents experienced each adversity to the mean in the absence of the adversity. The largest associations were observed for deprivation-type experiences, including poverty and low parental education, which were related to reduced IQ. Though lower in magnitude, threat events related to IQ included physical abuse and witnessing domestic violence. Violence prevention and poverty-reduction measures would improve childhood cognitive outcomes.