Continuity of drunk and drugged driving behaviors four years post-college

Abstract

Background: Driving under the influence of alcohol is a leading cause of injury and premature death among young adults, and college-educated individuals are at particularly high risk. Less is known about driving under the influence of other drugs, which is on the rise.

Method: This study describes prospective seven-year trends in alcohol and other drug (AOD)-involved driving among a young-adult sample beginning with their second year of college (i.e., Years 2-8), and documents the extent of continuity in such behaviors across time. Originally recruited as incoming first-year students at one large public university, participants (n=1194) were interviewed annually about how frequently they drove while drunk/intoxicated (DWI), after drinking any alcohol (DAD), and/or while under the influence of other drugs (DD). Follow-up rates were high (>75% annually).

Results: Among participants with access to drive a car, annual prevalence peaked in Year 4 (modal age 21) for both DWI (24.3%_wt) and DD (19.1%_wt) and declined significantly thereafter through Year 8 (both ps<0.05). DAD was far more prevalent than DWI or DD, increasing from 40.5%_wt in Year 2 to 66.9%_wt in Year 5, and plateauing thereafter. Among marijuana-using participants, likelihood of DD was consistently greater than the likelihood of DWI among Heavy Episodic and Light-to-Moderate drinkers, and it declined significantly during Years 5-8 (p<0.05).

Conclusion: Post-college declines in heavy drinking and DWI prevalence were encouraging but did not necessarily translate to reductions in likelihood of engaging in DWI, depending on drinking pattern. College-educated individuals represent an important target for AOD-involved driving prevention.

Keywords: Alcohol; College students; Driving after drinking; Drugged driving; Drunk driving; Marijuana.

Figure 1. Weighted annual prevalence of alcohol and other drug (AOD)-involved driving

Note. Results are restricted to individuals with access to drive a car during the past year. All data are weighted for sampling and attrition. Bars depict standard errors of the weighted population proportions. Superscripts denote years for which estimates are significantly different from a given estimate (p<.05), based on results of separate repeated measures analyses that were conducted using unweighted data.

Figure 2. Estimated probability of drugged driving (DD) and drunk driving (DWI) for selected subsets based on drinking pattern and marijuana use

Note. Results are restricted to individuals with access to drive a car during the past year. Results reported as estimated marginal means (standard errors) adjusting for year. Superscripts denote years for which estimates are significantly different from a given estimate (p<.05). All data are unweighted.

Figure 3. Weighted annual prevalence of Heavy Episodic drinking and marijuana use

Note. Results are statistically weighted to adjust for sampling and attrition. Results computed for the overall sample, regardless of access to drive a car (N_wt=3,285). Superscripts denote years for which estimates are significantly different from a given estimate (p<.05), based on results of separate repeated measures analyses that were conducted using unweighted data.