A Longitudinal Analysis of the Effect of Drinking Motives on the Impulsivity-Substance Use Relationship

Introduction: Emerging adulthood is a peak time for hazardous alcohol consumption (Littlefield et al., 2010).  Trait impulsivity has been implicated as a factor that is associated with harmful use. Impulsivity is defined as a lack of reflectiveness and planning, rapid decision-making and action, and carelessness (Schalling, 1978).  It is important to distinguish between different types of impulsivity, as they may have different relationships with harmful alcohol use (Magid, MacLean & Colder, 2007).  In addition, it is imperative to investigate how other factors may mediate these relationships.  One such factor is drinking motives.  Drinking motives describe why individuals make the decision to drink.  Adams et al (2012) investigated the relationship among facets of impulsivity, drinking motives, and problematic drinking with a cross-sectional sample.  Findings suggested that impulsive personality traits and drinking motives play important roles in determining the likelihood of problematic drinking (Adams, Kaiser, Lynam, Charnigo, & Milich, 2012).  The purpose of the present study is to investigate the longitudinal relationship among impulsivity traits, drinking motives, and harmful alcohol use.

Methods: In this longitudinal study, 259 freshman college students were followed over the course of three years.  Linear mixed effect models were used to determine the relationships among impulsivity (negative urgency, premeditation, and perseverance), drinking motives (coping & enhancement), and problematic drinking (harmful use, alcohol dependence, and highest use). 

Results: Results from the mixed models for longitudinal data found differing results for each dependent variable.  For harmful use, negative urgency was significant (p <.05), as well as its interaction with enhancement drinking motives (p <.05).  For alcohol dependence, negative urgency (p<.05), lack of premeditation (p<.01),  and the interaction between negative urgency and enhancement drinking motives (p<.01) were significant.  Lastly, for highest amount consumed, sensation seeking (p<.01), coping motives (p<.01) and the interaction between lack of premeditation and coping motives (p<.05) were significant. 

Conclusions: The results of this study underscore the importance of understanding factors that contribute to problematic drinking.  They suggest that researchers should look more specifically at impulsivity and how it may interact with drinking motives when developing interventions.  The findings have significant implications for preventing problematic drinking.