Drug exposure opportunities and use patterns among college students: results of a longitudinal prospective cohort study

Abstract

Underage drinking and drug use among college students are major public health concerns, yet few studies have examined these behaviors and their associated risk factors and consequences prospectively. This paper describes the sampling and recruitment methods of a longitudinal study of 1253 college students at a large, mid-Atlantic university. Incoming first-year students were screened during the unique window between high school and college in order to oversample drug users for longitudinal follow-up. Intensive recruitment strategies yielded a 95% cumulative response rate in annual interviews and semiannual surveys. The authors report preliminary results on exposure opportunity, lifetime prevalence, initiation, continuation, and cessation of substance use for alcohol, tobacco, and 10 illicit and prescription drugs during the first 2 years of college. Findings suggest that although some substance use represents a continuation of patterns initiated in high school, exposure opportunity and initiation of substance use frequently occur in college. Implications for prevention and early intervention are discussed.

Figure 1. Longitudinal Design of the College Life Study

Note: Each wave of data collection spanned several months. The timeline depicts the approximate timing of the beginning and end of each wave of data collection.

Figure 2. Sampling Design for the College Life Study

Figure 3. Cumulative Weighted Frequency of Exposure Opportunity to Use Alcohol, Tobacco, and 10 Other Drugs, By Age in Years

Graphed lines depict the weighted cumulative percent of all students who ever had the opportunity to try a substance by each age, as of the sophomore year of college. Circles on the graph indicate the age by which 50% of all students who were ever exposed to the substance had experienced their first opportunity. The mean age at first opportunity is reported for all students who ever had the opportunity to try a substance. Amphetamines include methamphetamine, but do not include prescription or over-the-counter medications.

Figure 4. Profile Analysis of Weighted Lifetime Prevalence of Drug Use in the College Life Study for Three Consecutive Assessments

Percentages in bold correspond to lifetime prevalence of use by sophomore year. Percentages in italics correspond to the percent increase in lifetime prevalence from pre-college to sophomore year. Amphetamines include methamphetamine, but do not include prescription or over-the-counter medications. Use of inhalants was not assessed prior to college, so no percent change is reported.