THE INTERGENERATIONAL TRANSMISSION AND IMPACTS OF ADVERSE CHILDHOOD EXPERIENCES

Abstract

Evidence that adverse childhood experiences (ACEs) are associated with a wide range of adverse health and behavioral outcomes, including poor behavioral outcomes, and increased substance use, has been expanded to demonstrate that ACEs may be a determinant in adverse health and behavioral outcomes across generations as well. To disentangle the intergenerational impacts of ACEs on select health and behavioral outcomes and inform future intergenerational research and practice, three separate studies were conducted as part of this investigation. The first is a systematic review assessing whether ACEs predict earlier age of initiation differently depending on substance, conducted to inform timing of ACE screening and substance use intervention within generations. Given evidence to suggest that maternal ACEs predict related behavioral outcomes, the association between ACEs and earlier age of substance use may extend across generations as well. Informed by the first study, the second study in this investigation assesses the association between maternal ACEs and offspring age of alcohol initiation. Because offspring concordant for higher intergenerational ACE exposure may be most susceptible to the intergenerational impacts of adversity, this study also assesses whether the association between maternal ACEs and offspring age of alcohol initiation is different depending on offspring ACE exposure. The third study of this investigation assesses the association between maternal ACEs and internalizing and externalizing behavior. Importantly, the well-established intergenerational continuity of adversity was considered conceptually and methodologically for the latter two studies. If there is a direct association of maternal ACEs on offspring outcomes independent of offspring ACEs, then ACE screening and intervention efforts should be expanded to include and consider maternal ACEs in addition to offspring ACEs. Therefore, the controlled direct effect of maternal ACEs, not through offspring ACEs, was estimated. Findings from the first study suggest that while ACEs are associated with earlier age of alcohol, nicotine, marijuana, and opioid initiation, often in a dose-dependent manner, ACEs may predict earlier initiation of alcohol and nicotine relative to other substances assessed. Three or more ACEs were associated with initiation of alcohol across multiple studies, with effect sizes (OR) ranging from 1.9 (95% CI: 1.7, 2.1) to 6.2 (95% CI: 4.6, 8.3). Among the youngest samples included in this review (aged 9-10), ACEs were positively associated with use of alcohol at the time of interview OR=1.3 (95% CI: 1.1, 1.5). Studies that assessed the association between ACEs and nicotine used thresholds between 15-17 to define early initiation and reported a range of effect sizes (OR) from 1.6 (95% CI: 1.2, 2.2) after exposure to more than one ACE to 5.2 (95% CI: 2.9, 9.3) after exposure to more than two ACEs. Exposure to two or more ACEs was associated with initiating vaping before age 11 (OR=3.4 (95% CI: 2.2, 5.4). While not rising to statistical significance (p<0.05), findings from the second study suggest there is a small inverse relationship between maternal ACEs and offspring age of alcohol initiation among the full sample. However, among offspring exposed to >2 ACEs themselves, 2 maternal ACEs are associated with =-1.4 (95% CI: -2.7, -0.1) and >2 maternal ACEs are associated with =-2.1 (95% CI: -3.8, -0.5) earlier age of alcohol initiation. These findings suggest that offspring exposed to high levels of intergenerational ACE exposure are at greatest risk for early alcohol initiation. Findings from the third study suggest that maternal ACEs are associated with offspring internalizing and externalizing behavior in a dose-dependent manner, independent of offspring ACE exposure. Specifically, 1, 2, and >2 maternal ACEs were independently associated with a 1.8 (95% CI: 0.9, 2.8), 2.1 (95% CI: 0.7, 3.4), and 2.7 (95% CI: 1.0, 4.4) increase in internalizing score and a 1.8 (95% CI: 0.8, 2.7), 3.1 (95% CI: 1.7, 4.4), and 3.3 (95% CI: 1.4, 5.1) increase in externalizing score, respectively. Taken together, findings from this investigation suggest that universal ACE screening in pediatric settings, particularly prior to onset of puberty, may identify youth for service provision prior to substance initiation and that maternal ACEs should be screened for and considered in addition to offspring ACE exposure to inform interventions related to adolescent substance use and internalizing and externalizing behavior. To that end, the prenatal period may be an opportune time for maternal ACE screening. Conclusions from these investigations may apply to the impact of maternal ACEs on other relevant offspring outcomes across the life course. Future directions for research, including assessment of relevant biological and psychosocial mechanisms, and potential moderators of identified associations are discussed.