Patterns of Substance Use and Associations with Mental, Physical, and Social Functioning: A Latent Class Analysis of a National Sample of U.S. Adults Ages 30-80.

OBJECTIVE: Trends show increased substance use among adults, yet little research on general population samples has examined differential patterns of licit and illicit substance use that can inform prevention and treatment efforts. This study identifies distinct patterns (classes) of substance use among 30- to 80-year olds, identifies demographic subgroups with the highest probability of class memberships, and compares classes on key indicators of functioning. Method: Participants (n = 1,877) were from the RAND American Life Panel. Online survey measures included current alcohol, tobacco, cannabis, and nonmedical prescription drug use, as well as mental, physical, and social functioning.
Results: Latent class analysis identified four classes: "Lighter Drinking" (46.6%), "Abstaining" (33.7%), "Heavy Drinking with Cigarette/Cannabis Use" (17.1%), and "Cigarette Smoking with Prescription Drug/Cannabis Use" (2.6%). Of these classes, "Cigarette Smoking with Prescription Drug/Cannabis Use" reported the worst mental and physical functioning, and greater loneliness than the "Lighter Drinking" class. "Heavy Drinking with Cigarette/Cannabis Use" reported worse mental and physical functioning than the "Lighter Drinking" class and less social support than the "Lighter Drinking" and "Abstaining" classes. The "Abstaining" class reported consistently worse functioning than the "Lighter Drinking" class. Both polysubstance use classes were associated with younger age, less education, and lower income, and heavy drinking polysubstance use was associated with being male and unmarried. Conclusions: Although lighter drinking was the most common pattern, 20% of adults were classified into two polysubstance use classes associated with poorer functioning. Targeted efforts may be needed to reach certain subgroups of adults who are particularly susceptible to polysubstance use.