Little is known about cannabis and tobacco co-use and its affect on the young adult population. With the growing popularity of marijuana, there has been an upward trend in those using marijuana and tobacco within a short time span. Studies have already found that 80-90% of those who use cannabis also use tobacco. This information is important due to its possible effects on individuals during emerging adulthood.

To complete the study, researchers recruited 6509 initial participants in the 6th and 7th grade. From there they followed them through 10 years to compete 10 waves of data collection. At each data collection they asked participants how many days they used cigarettes or marijuana throughout the past month. During the last collection they also asked about problem behaviors, mental and physical health, and social functioning. The researchers used a structural equation modeling framework to analyze the data. This type of framework allows them to model complex relationships between variables.

They found that overall there was a significant increase in co-use, cannabis only use, and tobacco only use over the span of the 10 waves. National data shows that this type of substance use typically peaks between the age of 18 and 25. This studies data shows that by the age of 21 almost 1 in 10 participants where co-using the substances. The researchers also found that those with higher probability of co-use reported higher rates of problematic behaviors as young adults. Higher levels of poor mental health were found to be associated with co-use of tobacco and cannabis. However, co-use was found to be associated with better social functioning. This might show that some identify themselves as “social users” and be at a higher risk for regular use. Co-use was found to be higher among white participants than Hispanic or Asian participants. This research is a first step in addressing the current gap in literature addressing co-use in emerging adults. It can provide important implications of co-use on functioning during this important time.

Take Away: Little research has been conducted on co-use of marijuana and tobacco use in the emerging adult population. This study followed participants starting in 6th or 7th grade for 10 years with 10 waves of data collection. They found that by the age of 21 almost 1 in 10 participants were co-using the substances. They also found that use of either or both increased over the span of the 10 waves. This provides knowledge for the trajectories of tobacco and marijuana use in emerging adults. More research should be complete to continue examining subgroups of people such as racial/ethnic differences and underserved populations

Tags: Marijuana, Tobacco, Young Adult

Tucker, J. S., Rodriguez, A., Dunbar, M. S., Pedersen, E. R., Davis, J. P., Shih, R. A., & D’Amico, E. J. (2019). Cannabis and tobacco use and co-use: Trajectories and correlates from early adolescence to emerging adulthood. Drug and Alcohol Dependence, 204, 107499. doi: 10.1016/j.drugalcdep.2019.06.004