A latent class analysis of heavy substance use in Young adulthood and impacts on physical, cognitive, and mental health outcomes in middle age.

Background: This study examines whether longitudinal patterns of persistent or experimental heavy substance use across young adulthood were associated with physical and mental health in midlife.

Methods: Data (N = 21,347) from Monitoring the Future from adolescence (age 18) to midlife (age 40) were used. Repeated measures latent class analysis modeled patterns of patterns of cigarettes, alcohol, marijuana, and other illicit drugs across young adulthood (ages 18-30). Latent classes were then used as predictors of physical health problems, cognitive problems, self-rated health, and psychological problems in midlife (age 40), while controlling for sociodemographic variables (i.e., gender, race/ethnicity, parental education).

Results: Identified classes were "Extreme Heavy Users" (3.9%), "Early Young Adult Users" (8.9%), "Cigarette Smokers" (9.2%), "All But Cigarette Smokers" (5.0%), "Frequent Alcohol Bingers" (10.4%), and "Not-Heavy Users" (62.6%). Extreme Heavy Users, Early Young Adult Users, and Cigarette Smokers had significantly poorer overall health based on a number of physical conditions and self-rated health. Extreme Heavy Users, Early Young Adult Users, Cigarette Smokers, and All But Cigarette Smokers had more cognitive problems than other classes. Extreme Heavy Users, Early Young Adult Users, Cigarette Smokers, and All But Cigarette Smokers were more likely to see a health professional for a psychological problem.

Conclusions: Patterns of heavy substance use were associated with health across decades. Regular cigarette smokers and heavy users across substances and ages had the worst health in midlife, although even those with time-limited use during young adulthood were at risk for later physical and cognitive health problems.