Many people consider alcohol to be more harmful than marijuana, study finds

As the national conversation about marijuana legalization continues, an important question is how changing marijuana policy may influence use of other substances, such as alcohol. A new study, led by researchers at RTI International, surveyed more than 1,900 adults in Oregon prior to the legalization of marijuana in the state and found that more than half (52.5%) consider alcohol to be more harmful than marijuana while few (7.5%) believe marijuana is more harmful to a person's health.

According to the study, published in the journal Preventive Medicine, younger people are substantially more likely to consider alcohol more harmful than marijuana to a person's health. Nearly 6 in 10 Democrats (57.9%), Independents (56.3%) and people with no political affiliation (61.5%) considered alcohol more harmful than marijuana, compared with less than one third of Republicans (30.7%). Most people who reported using both marijuana and alcohol considered alcohol more harmful than marijuana (67.7%), as did about half of those who used neither substance (48.2%).

"This study is the first to measure perceptions of the relative harmfulness of marijuana and alcohol," said Jane Allen, a research public health analyst in RTI's Center for Health Policy Science and Tobacco Research and study author. "The findings surprised me somewhat, because there is widespread acceptance of alcohol for adult recreational use, and in contrast, marijuana is classified at the federal level as a Schedule I drug. There seems to be a disconnect between the social and legal status of the substances and people's perceptions of harmfulness."

The RTI study notes that legalizing recreational marijuana will likely affect use of other substances, such as opioids and alcohol, and that perceptions of harmfulness may play a role. For example, research suggests that greater availability of marijuana may reduce reliance on opioids and other pain medications. The relationship between marijuana and alcohol appears to be more complex; marijuana functions as a substitute for alcohol in some contexts and as a complement in others. For this reason, it is unclear whether legalization of marijuana for recreational use will increase or decrease the significant social costs associated with alcohol.

Marijuana has been legalized for medical and recreational use in nine states and Washington, D.C., and for medical use in 20 other states.