Daily patterns of single and poly-substance use among adolescent and young adult females: A day-level latent class analysis

Background: Substance use is prevalent among adolescents and young adults (AYAs). Polysubstance use is associated with poorer outcomes than single substance use alone. However, few studies have examined patterns of daily use of substance(s) among AYA females, as well as associated factors. Objective: We aimed to 1) identify daily substance use patterns in AYA females, and 2) examine the association with select predisposing factors (i.e. impulsivity and depressive symptoms) and risky sexual behavior. Method: A sample of 15–24 year old females with recent binge drinking (n = 149), reported daily substance use and sexual activity through weekly Timeline Followback interviews over a 1-month period (n _days = 4224). Impulsivity, depressive symptoms, and sociodemographics were measured at baseline. Day-level latent class analysis was conducted to characterize patterns of substance use, and Bolck, Croon, and Hagenaars three-step approach was utilized to examine the association of predisposing factors and other health behaviors with latent class membership. Results: Four day-level classes of substance use were identified: 1) little-to-no-use (54.1 % of days); 2) vaping-only (28.2 % of days); 3) cannabis-only (10.5 % of days); and 4) heavy-alcohol-and-cannabis (some smoking and vaping; 7.2 % of days). More class 4 days were associated with higher impulsivity than class 1 and 3 (M = 0.42 vs. −0.17 and −0.13), more depressive symptoms than class 1 and 2 (M = 0.77 vs. −0.19 and 0.01), and more same day condomless sex than class 1 and 2 (19 % vs. 8 % and 7 %). Conclusions: AYA females exhibit varied patterns of daily substance use including polysubstance use. Knowledge of risk factors associated with problematic use as well as co-occurring risky sexual behavior can inform targeted intervention and prevention efforts.