E-cigarette and cannabis co-use surged among young adults from 2016 to 2021 while cigarette-cannabis co-use stayed flat or declined

E-cigarette and alcohol co-use increased among young adults (18-34), possibly replacing cigarette-alcohol co-use which declined. E-cigarette and cannabis co-use increased at Wave 5 among those 15-34, though this increase lessened at Wave 6 for most groups except ages 25-34. Cigarette-cannabis co-use rates were generally stable or decreasing.

Longitudinal analysis of PATH Study Waves 4-6 (December 2016 to November 2021) including all participants age 15+. Changes in past 30-day co-use of cigarettes, e-cigarettes, and other tobacco products with alcohol and cannabis were examined, moderated by age group and controlling for demographics.

Co-use of multiple substances carries risks beyond single-product use. As the substance landscape shifts toward vaping, understanding how co-use patterns evolve across age groups helps target public health messaging and intervention.

This study captures a pivotal period when vaping rapidly gained popularity. The apparent substitution of e-cigarettes for traditional cigarettes in co-use patterns suggests the substance landscape is reshaping rather than simply expanding.

Self-reported data. Co-use defined as same 30-day period, not necessarily simultaneous use. Data ends November 2021, missing post-pandemic recovery period. Broad product categories may mask important variation.