The influence of stress and early life adversity on addiction: Psychobiological mechanisms of risk and resilience.

Preclinical, clinical, and population research demonstrates that stress and early life adversity (ELA) increase vulnerability to initiate, maintain, and relapse in addiction. Individuals with addiction problems have higher prevalence of trauma exposure than nondrug users; and this association extends to young populations (e.g., adolescents). Mechanisms for these associations likely involve multiple systems, including changes in the mesolimbic reward functions, HPA axis stress response, and other stress- and reward-related pathways. Other brain morphological and functional changes are also likely involved and directly contribute to the neurohormonal and behavioral alterations observed during adulthood in those exposed to ELA. Stress-related risk is influenced by sex, genetic factors, and resilience, among other factors. Our heuristic model proposes that long-term effects of stress and ELA on the brain contribute to dysregulation of the stress response, emotional reactivity, reward systems, cognitive dysregulation, and delay discounting that lead to impulsive and high-risk behaviors, such as drug use and relapse.