Abstract
INTRODUCTION: This study examined US young adults' cannabis-tobacco use classes. METHODS: Latent class analysis used 2023 data among young adults (ages 18-34, purposively recruited via Facebook to represent ~50% past-month cannabis use), specifically the 2267 reporting past-month cannabis and/or tobacco use. Indicators included: cannabis, cigarette, and e-cigarette use (0 days, infrequent [1-10], frequent [11-30]) and any cigar, hookah, smokeless tobacco, and nicotine pouch use. Multivariable regressions examined sociodemographics, adverse childhood events (ACEs), mental health, and personality characteristics in relation to class. RESULTS: Five classes were identified: (#1) "primarily cannabis" (36.6%): all used cannabis (74.0% infrequent), <14% tobacco products; (#2) "frequent cannabis-cigarette" (34.2%): 86.7% cannabis (82.9% frequent), 65.9% cigarettes (51.6% frequent), 59.4% e-cigarettes (33.6% frequent), <37% other tobacco; (#3) "product-dabbling" (16.0%): 79.8% cannabis, 71.8% cigarettes, 66.7% e-cigarettes (largely infrequently used each), <40% other tobacco; (#4) "frequent poly-product" (7.7%): 93.9% cannabis, 90.9% cigarettes, 98.2% e-cigarettes (~half frequently used each), >84% other tobacco; and (#5) "primarily e-cigarette" (5.5%): all used e-cigarettes (51.0% frequent), <9% other tobacco. Correlates of class #4 membership were: being Black (vs. White) and more mental health symptoms vs. other classes; being Hispanic vs. #2 and #5; being heterosexual (vs. other) vs. classes #1-#3; being older and male and higher extraversion vs. #1 and #5; in non-legalized states vs. #1; more ACEs vs. #1, #3, and #5; and higher neuroticism and less openness vs. #1-#2. CONCLUSIONS: The frequent poly-product class represented characteristics (e.g., race/ethnicity, sexual minority, mental health) implicated in substance use related disparities, underscoring the need for targeted intervention.