Co-use of alcohol and cannabis is becoming more popular among college students with around 47.3% of students reporting consuming both substances during the past 30 days. Among this group, 75.8% report using alcohol and cannabis simultaneously. Co-use of these substances can result in a variety of adverse effects including lower academic performance, mental health conditions, and cognitive impairment. On the other hand, some studies have found that cannabis may be used a substitute for alcohol, thereby decreasing alcohol consumption and its negative consequences. However, this effect may be mediated by the order in which the substances are used. This study examines the effect of alcohol and cannabis use order on frequency, quantity, and consequences of alcohol and cannabis use among college students.
The study’s sample consisted of 401 college students who reported using both alcohol and cannabis during the past 30 days. Participants were asked to report the total number of days during the last 30 days that they used cannabis or alcohol, number of grams of cannabis used each day during a typical week, and number of drinks consumed each day during a typical week. Students were also asked to indicate number of days in which they used alcohol first, number days in which they used cannabis first, number of days in which they used alcohol last, number of days in which they used cannabis last, and number of days in which the effects of alcohol and cannabis overlapped (simultaneous use). Lastly, cannabis and alcohol-related consequences were assessed. Data was analyzed using path analysis.
Results of the data analysis showed that simultaneous use days were associated with 7% fewer cannabis consequences, 6% fewer alcohol use days, 10% fewer cannabis used days, 0.31 fewer grams of cannabis used, and 0.62 less drinks consumed during a typical week. Each additional day of using cannabis first was associated with 12% fewer alcohol-related consequences, 6% fewer alcohol use days, 21% more cannabis use days, and 0.75 more grams of cannabis used in a typical week. Each additional day of using alcohol first was associated with 14% fewer cannabis-related consequences, 11% more alcohol use days, and 1.72 more drinks consumed during a typical week.
Takeaway: Alcohol and cannabis use order may affect alcohol and substance use outcomes among college students who report simultaneous use of alcohol and cannabis.