Early Birds and Night Owls: Distinguishing Profiles of Cannabis Use Habits by Use Times with Latent Class Analysis

Negative consequences associated with excessive use of cannabis are well documented. Previous findings indicate timing of use is an important factor when assessing severity of dependence for use of substances including alcohol and cigarettes. However, little attention in the academic literature has been paid to timing of cannabis use and its associations with negative consequences. The present study employed a latent class analysis on data collected from college students who use cannabis, located across four U.S. universities in four different states (N = 1,122). The goal was to examine whether distinct classifications of cannabis use exist based on timing (i.e., hour of day and day of week), and whether these classifications differ on cannabis use indicators (Marijuana Use Grid; MUG), cannabis-related negative consequences (Marijuana Consequences Questionnaire; MACQ), and cannabis use disorder symptoms (Cannabis Use Disorder Identification Test-Revised; CUDIT-R). The MUG assesses the amount (in grams) of cannabis used during a week of typical marijuana use in the past 30 days on each of the seven days per week (Monday-Sunday) during each of six 4-hour time periods (12a-4a, 4a-8a, 8a-12p, 12p-4p, 4p-8p, 8p-12p). By summing across time periods for each day, we binarized the presence of cannabis use (0 = no use, 1 = use) for each day of the week. By summing across days for each time period, we binarized the presence of cannabis use for each time period. Based on the Lo-Mendell-Rubin Likelihood Ratio Test (LRT) and other fit indices, we found support for a 4-class solution with high classification precision (relative entropy = .905). The four classes were characterized as follows: (1) daily (greater than 98% of the class endorsed use on each day of the week), common morning use (N = 140.17, 12.5%), (2) daily (greater than 88% of the class endorsed use each day of the week), uncommon morning use (N = 241.02, 21.5%), (3) weekend, common morning use (N = 72.22, 6.4%), and (4) weekend, uncommon morning use (N = 668.59, 59.6%). Individuals reporting daily, common morning use experienced the highest cannabis-related negative consequences (MACQ M = 7.53) and reported the highest levels of cannabis use disorder symptoms (CUDIT-R M = 15.74), whereas individuals reporting weekend, uncommon morning use experienced few cannabis-related negative consequences (MACQ M = 2.24)) and reported low cannabis use disorder symptoms (CUDIT-R M = 5.45). Taken together, our classes were defined by crossing the presence/absence of morning cannabis use by the presence/absence of weekday cannabis use, and we found evidence that both the timing of week and timing of day contribute to the level of cannabis-related harms that individuals experience. Additional research is needed to explore the unique contributions of time of week and time of day while controlling for other characteristics of one’s cannabis use (i.e., frequency, quantity, product type, route of administration, etc.).