Nearly 1 in 4 12th grade (modal age 18 years) frequent marijuana users in the US continues to report high frequency use through age 30, according to a recent study. Furthermore, the proportion continuing high frequency use across young adulthood has increased among more recent cohorts. Researchers conducted a longitudinal national panel data from 4,423 individuals (53.4% of the eligible sample; 2,744 [62%] males) who reported frequent marijuana use in 12th grade followed biennially from age 19/20 through 29/30. Subjects self‐reported past 30‐day marijuana use (frequent use defined as use on ≥20 occasions), demographics, college graduation, marriage, and parenthood. They found:
- Repeated measures latent class analysis identified 5 latent classes of past 30‐day marijuana use from ages 19/20 through 29/30: 1) Continued Frequent Users (estimated membership 23.4%); 2) Frequent to Non‐Frequent Users (15.5%); 3) Consistent Non‐Frequent Users (18.4%); 4) Non‐Frequent Users to Discontinuers (19.5%); and 5) Discontinuers (23.2%).
- In multivariable models, membership in the highest‐risk latent class (Continued Frequent Users) vs ≥1 of the lower‐risk latent classes was more likely for recent cohorts, as well as those who did not marry or become parents by modal age 29/30.
Terry-McElrath YM, O’Malley PM, Johnston LD. Schulenberg JE. Young adult longitudinal patterns of marijuana use among US national samples of 12th grade frequent marijuana users: A repeated measures latent class analysis. [Published online ahead of print January 4, 2019]. Addiction. doi:10.1111/add.14548