Prevalence of medical marijuana use in California, 2012

The US Drug Enforcement Agency classifies marijuana as an illegal substance, yet in 22 states marijuana is legal for medicinal use. In 1996, California legalised the use of marijuana for medicinal purposes, but population-based data describing medical marijuana users in the state has not been available. Our aim was to examine the demographic differences between users and non-users of medical marijuana in California utilising population-based data.

We used data from the California Behavioral Risk Factor Surveillance System 2012, an annual, random-digit-dial state-wide telephone survey that collects health data from a representative adult sample (n = 7525). Age-adjusted prevalence rates were estimated.

Five percent of adults in California reported ever using medical marijuana, and most users believed that medical marijuana helped alleviate symptoms or treat a serious medical condition. Prevalence was similar when compared by gender, education and region. Prevalence of ever using medical marijuana was highest among white adults and younger adults ages 18-24 years, although use was reported by every racial/ethnic and age group examined in our study and ranged from 2% to 9%.

Our study's results lend support to the idea that medical marijuana is used equally by many groups of people and is not exclusively used by any one specific group. As more states approve marijuana use for medical purposes, it is important to track medical marijuana use as a health-related behaviour and risk factor.