Date Available


Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Arts and Sciences



First Advisor

Dr. Richard Milich


Impulsive personality traits have been found to be robust predictors of substance use and problems in both cross-sectional and longitudinal research. Studies examining the relations of substance use and impulsive personality over time indicate bidirectional effects, where substance use is also predictive of increases in later impulsive personality. The mechanism(s) accounting for the impact of substance use on later personality remain unknown. The present study sought to explore the bidirectional relations of alcohol use with the impulsive personality traits over three time points, and to examine two potential mechanisms that could account for the impact of alcohol use on personality: the development of alcohol-related problems and social norms for substance use. Participants were 525 college students (48.0% male, 81.1% Caucasian), who completed self-report measures assessing personality traits and a structured interview assessing past and current substance use. Data collection took place at three different time points: the first occurred during participants’ first year of college (T1), and follow-ups took place approximately one-year (T2) and two-years (T3) later. Bidirectional relations were examined using structural equation modeling to control for the relations among the variables of interest within time points and the stability of the variables across time. T1 sensation seeking and lack of premeditation predicted higher levels of alcohol use at T3, and T1 alcohol use predicted higher levels of all three impulsive traits at T3. T2 friend norms for drug use were found to significantly mediate the relation between T1 alcohol use and T3 sensation seeking, and T2 alcohol problems were found to significantly mediate the relation between T1 alcohol use and T3 negative urgency. Findings provide greater resolution in characterizing the bidirectional relation between impulsive personality traits and substance use, and demonstrate that sensation seeking and negative urgency are impacted through distinct mechanisms.