Substance-related traffic-risk behaviors among college students

Drunk driving is a major public health concern, but drugged driving has received little attention. This study examines drugged driving and riding with a drugged driver in a college student sample, in terms of prevalence, age-related trends, race/sex differences, overlap with drunk driving, and risk for alcohol and marijuana dependence.

Students (N=1194) ages 19-22 were interviewed annually for 3 years about past-year frequency of drugged driving, riding with a drugged/drunk driver, drunk driving, access to a car, and alcohol/drug dependence. Annual follow-up rates were excellent (88-91%). Repeated measures analyses were conducted using generalized estimating equations (GEE).

One in six (17%(wt)) 19-year-olds with access to a car drove drugged in the past year; prevalence remained stable through age 22. Drugged driving was more prevalent among males (p<.001) and whites (p<.01). Riding with a drugged driver varied by race and sex (overall prevalence 28%(wt) at age 19), was stable from age 19 to 21, and decreased by age 22 (p<.05). Annually, half of drugged drivers also drove drunk (ranges between 47% and 60%). Both drugged and drunk driving were independently associated with increased risk for alcohol dependence, holding constant age, sex, and race. Drunk driving did not add to the risk for marijuana dependence in the context of drugged driving.

The prevalence of drugged driving is similar to drunk driving among college students. Both are strongly associated with underlying alcohol and drug dependence. Prevention and treatment implications are discussed.