A recent study prospectively examined relationships between marijuana use and health and social measures among U.S. emerging adults. Data from the NEXT Generation Health Study (a longitudinal study of a nationally representative sample) were obtained; participants completed annual assessments from 10th grade (Wave 1) to two years past high school graduation (Wave 5). For this study, a subsample of 1,915 participants (38.8% male) with data on marijuana use at Wave 4 and participation in Wave 5 were selected. Assessment measures included frequency of past-year marijuana use, negative health measures (sedentary behaviors, being overweight/obese, unhealthy weight control behaviors, psychosomatic symptoms [i.e., headache], depressive symptoms, risky driving behaviors [i.e., distracted driving, riding with a cannabis-impaired driver], low academic achievement), and sociodemographic characteristics. Positive health measures, including physical activity, fruit and vegetable consumption, optimism, positive health perception, school attendance, and high academic achievement, were also assessed. Based on their Wave 4 responses, participants were classified as past-year marijuana never users, (69.2%), occasional users (those who reported using marijuana one to 19 times; 20.2%), or frequent users (those who reported marijuana use 20 or more times; 10.7%). To analyze these data, the authors constructed three multinomial logistic regression models for each outcome. Model 1 included marijuana use, gender, ethnicity, family affluence, parent education, family structure; Model 2 added alcohol and tobacco; Model 3 added health status and the Wave 4 variable for the outcome. Additionally, the authors used multinomial logistic regressions to indicate p-values for differences between adjusted odds ratios (AORs) for the frequent and occasional groups. Results indicated that higher proportions of participants in the occasional and frequent use groups reported negative health and social measures at one year, compared to the no use group. For example, 60.5% of the frequent use group and 56.0% of the occasional use group reported negative psychosomatic symptoms at follow-up, relative to only 50.8% of the no use group. For positive measures, the relationships with group membership were mixed. Results of Model 3 indicated participants in the frequent use group had higher odds (relative to non-users) of being at higher risk for the following behaviors one year later: Risky driving behaviors (AOR = 1.78, confidence interval [CI] = 1.45-2.19), depressive symptoms (AOR = 1.68, CI = 1.43-1.98), unhealthy weight control behaviors (AOR = 1.55, CI = 1.31-1.84), psycho-somatic symptoms (AOR = 1.55, CI = 1.30-1.83) and low school achievement (AOR = 1.46, CI = 1.23-1.75). Participants in the occasional use group were more likely to report self-perceived good health (AOR = 1.49, CI-1.30–1.71), attending college (AOR = 1.43, CI-1.18–1.73), and having educational aspirations (AOR = 1.56, CI-1.35–1.80) than members of the other groups at follow-up.

Take away: In this study, emerging adults who reported occasional or frequent marijuana use at baseline had greater odds of reporting negative outcomes one year later, compared to their peers who reported no use at baseline. However, occasional users had greater odds of reporting being in good health and attending college at follow-up.

Korn, L., Haynie, D.L., Luk, J.W. & Simons-Morton, B.G. (2018). Prospective associations between cannabis use and negative and positive health and social measures among emerging adults. International Journal of Drug Policy [published online ahead of print May 25, 2018] doi: 10.1016/j.drugpo.2018.05.003