Impulsivity as a mechanism linking child abuse and neglect with substance use in adolescence and adulthood.

Emerging developmental perspectives suggest that adverse rearing environments promote neurocognitive adaptations that heighten impulsivity and increase vulnerability to risky behavior. Although studies document links between harsh rearing environments and impulsive behavior on substance use, the developmental hypothesis that impulsivity acts as mechanism linking adverse rearing environments to downstream substance use remains to be investigated. The present study investigated the role of impulsivity in linking child abuse and neglect with adult substance use using data from (a) a longitudinal sample of youth (Study 1, N = 9,421) and (b) a cross-sectional sample of adults (Study 2, N = 1,011). In Study 1, the links between child abuse and neglect and young adult smoking and marijuana use were mediated by increases in adolescent impulsivity. In Study 2, indirect links between child abuse and neglect and substance use were evidenced via delayed reward discounting and impulsivity traits. Among impulsivity subcomponents, robust indirect effects connecting childhood experiences to cigarette use emerged for negative urgency. Negative urgency, positive urgency, and sensation seeking mediated the effect of child abuse and neglect on cannabis and alcohol use. Results suggest that child abuse and neglect increases risk for substance use in part, due to effects on impulsivity. Individuals with adverse childhood experiences may benefit from substance use preventive intervention programs that target impulsive behaviors.

Interrelationships among parental family history of substance misuse, delay discounting, and personal substance use.

RATIONALE: Despite consistent evidence of the familiality of substance misuse, the mechanisms by which family history (FH) increases the risk of addiction are not well understood. One behavioral trait that may mediate the risk for substance use and addiction is delay discounting (DD), which characterizes an individual's preferences for smaller immediate rewards compared to larger future rewards. OBJECTIVES: The aim of this study is to examine the interrelationships among FH, DD, and diverse aspects of personal substance use, and to test DD as a mediator of the relationship between FH and personal substance use. METHODS: The study used crowdsourcing to recruit a community sample of adults (N = 732). Family history was assessed using a brief assessment of perceived parental substance use problems, personal substance use was assessed using the Alcohol Use Disorders Identification Test and a measure of frequency of use, and delay discounting was assessed using a latent index of discounting preferences across six reward magnitudes. RESULTS: Steeper discounting was significantly associated with personal alcohol, tobacco, and marijuana use, and level of substance experimentation. Steeper DD was also associated with a denser parental FH of alcohol, tobacco, and overall substance misuse. Parental FH density was significantly associated with several aspects of personal substance use, and these relationships were partially mediated by DD. CONCLUSIONS: The current study suggests that impulsivity, as measured by DD, is one proximal mechanism by which parental FH increases substance use later in life. The causal role of DD in this relationship will need to be established in future longitudinal studies.