Associations between early childhood adversity and behavioral, substance use, and academic outcomes in childhood through adolescence in a US longitudinal cohort

Background: Childhood adversity is strongly associated with adolescent substance use, but few epidemiologic studies have investigated early childhood adversity (ECA) before age 5. This study investigated pathways by which ECA is associated with adolescent alcohol and cannabis use and high school completion through childhood behavioral and academic mediators and their reciprocal effects.Methods: Data were from the National Longitudinal Survey of Youth 1979-Child/Young Adult Cohort which surveyed children born 1984-1999 and followed through 2016 (n = 5521). Outcomes included alcohol and cannabis use frequency at ages 15-18, and high school completion by age 19. ECA at ages 0-4 was a cumulative score of maternal heavy drinking/drug use, low emotional support, low cognitive stimulation, and household poverty. Multilevel path models were conducted with ECA, childhood mediators (behavioral (externalizing and internalizing problems) and academics (reading and math scores), accounting for demographics and confounders. Results: ECA was indirectly associated with adolescent cannabis frequency through mediators of externalizing/ internalizing problems, low academics, and early cannabis onset before age 14. ECA was also indirectly asso-ciated with alcohol frequency via the same mediators, but not early alcohol onset. Greater behavioral problems elevated substance use risk; whereas, low academics reduced risk. Reciprocal effects were evident between childhood behavioral problems and cannabis frequency to high school completion.Conclusion: Adversity from birth to age 4 is associated with childhood behavioral problems and lower academics, which increased adolescent alcohol and cannabis use and lowered high school completion. Early childhood in-terventions with parents and preschools/daycare may reduce early onset and adolescent substance use.