Early life adversity and substance use: The mediating role of mood and the moderating role of impulsivity

Introduction: Early life adversity (ELA) is a risk factor for substance use and misuse, and multiple factors mediate and moderate this association. We examined whether moods mediate the relationships between ELA and nicotine use, cannabis use, and co-use, and whether these mediation effects varied as a function of delay discounting. Methods: A total of 2555 adults completed a delay discounting task and responded to questions related to demographics, ELA, mood, and substance use. Data were analyzed using Pearson correlations and moderated mediation using Hayes' PROCESS macro (V3.4, Model 15). Results: ELA was positively associated with cannabis use, nicotine use, co-use of both substances, depressed and stressed moods, and it was negatively associated with positive mood. While cannabis use was associated negatively with stressed and depressed moods and positively with positive mood, nicotine use was associated negatively with positive mood. Moderated mediation analyses indicated that positive mood mediated the relationship between ELA and cannabis use for those with average and above average delay discounting. Positive mood also mediated the relationship between ELA and co-use among those with above average delay discounting. Conclusion: The results suggest that ELA's associations with cannabis use and cannabis-nicotine co-use may be partially attributable to ELA's effects on positive mood among those who are predisposed to moderately to highly impulsive decision making.