Latent Classes of Substance Use in Young Adults - A Systematic Review

Background: This systematic review provides an overview of studies on latent classes related to the substance use among young adults (18-25 years). Identifying these classes helps to detect high-risk groups, setting a base for selective prevention.Methods: This systematic literature review included peer-reviewed studies (published up to February, 2021) that identified latent classes and investigated predictors of latent classes relating to the use of marijuana, alcohol and/or other substances within samples of young adults.Results: Twenty studies (sample sizes N = 171 to N = 21945) met the inclusion criteria. 14 studies identified 'low-level engagers', 'light alcohol and tobacco use', 'heavy alcohol and tobacco use' and 'heavy use/polysubstance use' classes. Four studies differentiated within the 'heavy/polysubstance' class and found 'traditional clubdrugs', 'hallucinogens' and 'wide-range illicit drugs' classes. Male gender and white race predicted membership of the 'heavy use/polysubstance use' class consistently across studies. Other predictors of polysubstance use that were consistent across studies were peer substance use, depressive symptoms, parental drinking and participating in an honor society.Conclusions: The investigated predictors of class membership provide insight into social settings and characteristics that predict heavy use or polysubstance use. They can contribute to the development of effective prevention interventions by allowing for a more targeted approach.