Social
Mechanisms linking adverse childhood experiences to co-occurring mental health and substance use disorder in young adulthood Ethan Ecret* Ethan Ecret Elizabeth Vasquez Allison Appleton Tomoko Udo Muntasir Masum Melissa Tracy
Adverse childhood experiences (ACEs) are linked to poor health outcomes later in life, though the mechanisms connecting ACEs to health outcomes in young adulthood are less understood. This study explores the extent to which behavioral and psychosocial factors mediate the relationship between ACEs and co-occurring mental health and substance use disorders (SUD) in young adulthood. We used data from 3,420 participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Using semiparametric group-based trajectory modeling, we identified five childhood adversity trajectories from birth through age 12: stable low (57.1%), stable mid (30.2%), increasing from mild to high (6.7%), decreasing from moderate to mid (4.0%), and stable high (2.1%). At age 24, 16.7% of participants met criteria for a mental disorder (e.g., depression, anxiety) only, 11.3% met criteria for alcohol use disorder (AUD) or cannabis use disorder (CUD) only, and 6.4% met criteria for both mental health and substance use disorders. In multinomial logistic regression models, adjusted for socio-demographics and maternal factors, ACEs were associated with mental health and substance use disorders, with participants with stable-high adversity showing the highest odds of mental health disorders only (OR=2.00, 95% CI=1.09-3.67), those with decreasing adversity showing the highest odds of AUD and/or CUD (OR=2.02, 95% CI=1.18-3.45), and those with increasing adversity showing the highest odds of both mental health and substance use disorders (OR=2.31, 95% CI=1.39-3.84), all relative to those with stable low adversity. Substance use, impulsivity, antisocial activities, and internalizing problems in adolescence together explained 7-32% of the estimated effects of ACEs. Early intervention among children with ACEs is critical, but targeting behavioral and psychosocial factors in adolescence may also help reduce progression to co-occurring mental health and substance use problems in young adulthood.