Age-related patterns in high-risk alcohol and cannabis use and their associations with positive and negative affect in young adulthood.

Simultaneous alcohol and cannabis use and heavy episodic drinking are high-risk behaviors that have been associated with a host of negative health, social, and safety consequences (e.g., Duckworth and Lee, 2019, Lee et al., 2022, Sloan et al., 2011, Subbaraman and Kerr, 2015, Yurasek et al., 2017). Nationally representative studies indicate that the prevalence of these behaviors is at its highest among young adults in their twenties (Subbaraman & Kerr, 2015) and is not limited to college students (Lee et al., 2022, Linden-Carmichael and Lanza, 2018, Patrick et al., 2019). Understanding whether there are specific ages when there is a heightened risk of engaging in these behaviors could help improve developmental focus of preventive and interventive efforts. However, only a few studies have examined developmental trajectories of simultaneous use with any rigor (Lee et al., 2022) and none have focused on a sample of young adults in the context where both alcohol and cannabis are legal to use for those 21 and over. Studies examining developmental trajectories of heavy episodic drinking (HED; sometimes referred to as “binge drinking”) are more numerous and indicate that there is developmental variability in HED use over the course of young adulthood. Specifically, a large body of work suggests that the normative developmental pattern of HED involves increases in HED from late adolescence through the early 20’s, peaks at ages 22 or 23, and then follows a gradual decline throughout the twenties both at the individual and population levels (e.g., Cadigan et al., 2019, Maggs and Schulenberg, 2004, Nelson et al., 2015, Patrick et al., 2022, Schulenberg and Maggs, 2002).

Little is known about the strength of the association between HED and simultaneous alcohol and marijuana/cannabis use (SAM) over the course of young adulthood. Studies focusing on adolescents have found that SAM is strongly and positively associated with HED particularly among high school seniors (e.g., Patrick et al., 2017). Studies of young adults have found positive associations among SAM, alcohol, and cannabis use amount and frequency (for review, see Lee et al., 2022). If the strength of the association between SAM and HED remains relatively stable over the course of young adulthood, the selection of effective prevention and intervention tools aimed at reducing these health risk behaviors could be streamlined. If, however, the association varies over time, then this would provide evidence of a need for tools that target specifically SAM and HED. For example, it may be that this association is particularly strong around age 21 when the use of both substances becomes legal for young adults in many states. Indeed, studies have clearly demonstrated an association between turning 21 and increases in hazardous drinking and cannabis use (Gilson et al., 2022). Developmental periods when the association between SAM and HED is particularly strong are of especially high risk for young adults’ health and well-being and therefore important developmental time for preventive interventions.

Importantly, our understanding of the psychological context of when young adults engage in these behaviors is limited. Yet, psychological context is an important correlate of substance use. Positive affect has been positively associated with alcohol use (Bresin & Fairbairn, 2019; for review, see e.g., Dora et al., 2023) and HED (Patrick et al., 2016, Stevenson et al., 2021) but whether these associations vary over the course of young adulthood is unclear. Conversely, negative affect has been associated with a higher prevalence of and more frequent cannabis use (Choi et al., 2022, Patrick et al., 2016, Rhew et al., 2021) and also hazardous drinking (e.g., Crum et al., 2013; McHugh & McBride, 2020) and, more recently, SAM (Fleming et al., 2021, Lee et al., 2022) but we do not know whether the strength of these associations remains stable or waxes and wanes over the course of young adulthood. For example, it is possible that the association between positive affect and high-risk substance use is at its strongest around the 21st birthday (Gilson et al., 2022) but declines afterwards. It is also possible the associations of negative affect with HED and SAM become stronger after young adults reach the legal age to access alcohol and cannabis and their use becomes more commonplace (Patrick et al., 2022). Gaining knowledge about the potential age-varying associations between affect with HED and SAM could further improve the design of effective preventive interventions.

Thus, the current study had two aims. First, we examined age-related patterns in the prevalence of past-month SAM and past-month HED during young adulthood, and the age-varying association between these two high risk behaviors. Second, we examined age-varying associations between positive and negative affect and past-month SAM and HED in a sample of young adults that initially resided in a state where the use of both cannabis and alcohol is legal for those 21 and older.