Is Childhood Adversity Before Age 5 Associated with Adolescent and Young Adult Substance Use? Findings from a US Prospective Cohort Study

Objective: Growing research suggests that adversity experienced early in life can affect young children's development, with implications for health-related outcomes years later. This study explored long-term associations between early life adversity before age 5 (ELA) and later substance use outcomes, and racial and ethnic differences in associations. Method: Data are from children born 1984-2000 to female participants in the U.S. National Longitudinal Study of Youth-1979 cohort (N = 4582 children nested within 2683 mothers, with 1.4-1.8 outcome observations on average for each child in each age period). ELA at ages 0-4 was measured through home observations and maternal surveys, and included high parental conflict and maternal hazardous drinking/drug use (threat-related exposures), and low cognitive stimulation, low emotional support, and household poverty (deprivation-related exposures). Alcohol and cannabis use frequency were measured in biennial adolescent and young adult surveys through 2016. Analyses involved multilevel regression and interactions accounting for demographics, birth cohort, and family history of alcoholism. Results: ELA-threat exposure was associated with greater alcohol and cannabis use frequency in mid-adolescence and at ages 22-25 and 26-32 [exp(beta<^>)'s = 1.05 to 1.13, p's < 0.05]. Associations of ELA-deprivation with substance use were either null or negative. There were pronounced racial and ethnic inequities in ELA exposure but no evidence of racial and ethnic differences in associations between ELA and later substance use. Conclusions: Broadening substance use research to focus on early childhood conditions appears warranted. Studies that identify intervening pathways to outcomes could inform early, targeted substance use prevention. Efforts are needed to eliminate racial and ethnic inequities in early life conditions.