College students across seven countries fell into three substance use classes, with polysubstance users showing higher impulsivity and childhood adversity

Three substance use classes emerged: polysubstance users, alcohol-marijuana-tobacco co-users, and primarily drinkers. Polysubstance users had significantly higher adverse childhood experiences, more ruminative thinking, and greater impulsivity than the other classes. Country-level comparisons showed the US was most similar to Spain, Argentina, and Uruguay in alcohol-marijuana-tobacco co-use.

Latent class analysis of an online survey of 9,065 college students (71% women) from the US, Canada, South Africa, Spain, Argentina, England, and Uruguay. Classes were derived from lifetime use of multiple substances. Between-class differences in adverse childhood experiences, ruminative thinking, and impulsivity-like traits were tested.

Identifying which college students are at highest risk for polysubstance use and what psychological factors distinguish them can help universities target prevention programs more effectively, especially since these vulnerability factors are potentially modifiable.

Polysubstance use among college students is not just about access or culture. The finding that childhood adversity and psychological traits differentiate use patterns suggests that early intervention for trauma and emotion regulation could prevent escalation.

Convenience sampling. Lifetime use measure does not capture current patterns or frequency. Cross-sectional design. Self-reported data. The 71% female sample may not represent all college populations.