What is the impact of recreational marijuana legalization on the development of marijuana use and marijuana use disorders, alcohol, nicotine, and other substance use and use disorders, and associated psychological adjustment and psychopathology?
We are comparing two twin samples that have been followed longitudinally for over 15 years since adolescence. One of these samples is from Colorado, which legalized adult recreational marijuana use in 2014 and now has widespread commercial marijuana readily available to consumers. The other sample is from Minnesota, which in 2014 legalized medical marijuana, with very strict limits on access, but has not yet legalized recreational use. Together with prior longitudinal data, our new surveys will help us understand the impact of recreational marijuana legalization and marijuana use on a wide variety of important outcomes.