Adult marijuana use rose significantly in states that passed loosely regulated medical marijuana laws (MMLs) according to a new study by Columbia University’s Mailman School of Public Health and Columbia University Medical Center. Highest increases were reported among adults ages 26 and over. Little change was found in past-month marijuana use among adolescents or young adults between the ages 18 and 25. The findings are published online in the journal Addiction.
Adults 26 years of age and older living in states with less regulated medical marijuana programs increased past-month marijuana use from 4 percent to 6.59 percent after the laws were enacted. No significant change was found in the prevalence of cannabis use disorder among adolescents or adults after states enacted medical marijuana laws, regardless whether programs were highly regulated or “loose.”
Using data from the National Survey of Drug Use and Health from 2004-2013 the researchers analyzed trends over time with particular emphasis on age groups. This included obtaining prevalences of marijuana use outcomes at the state level by year and whether the enacted laws included a highly regulated (“medicalized”) or less regulated (“non-medical”) program. Participants were classified as having marijuana abuse or dependence based on DSM-IV criteria.