States that allow medical marijuana have 25 percent fewer prescription drug overdose deaths, a team of researchers reports in a newly released academic paper, suggesting that expanded access to marijuana, often used for its purported pain-alleviating qualities, could have unintended benefits.
As awareness of the addiction and overdose risks associated with painkillers such as OxyContin and Vicodin grows, "individuals with chronic pain and their medical providers may be opting to treat pain entirely or in part with medical marijuana," Colleen Barry, an associate professor in the Department of Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health, said in a statement. Barry was the senior author of the study, which was conducted by researchers from the Bloomberg School and the Philadelphia Veterans Affairs Medical Center.
The researchers found that states with medical marijuana laws consistently had lower overdose death rates throughout the years studied -- 1999 to 2010 -- and that such laws were associated with a 24.8 percent lower annual rate of painkiller overdose deaths. Those states had 1,729 fewer overdose deaths in 2010 than would have been predicted by trends in states without such laws.
To conduct their analysis, published Monday in the peer-reviewed JAMA Internal Medicine, the researchers relied on Centers for Disease Control and Prevention death certificate data. The rate of overdose deaths rose in all states over the study period. California, Oregon and Washington were the only three states with medical marijuana laws in place before 1999, while ten more had joined by 2010.
Although the results seem to suggest that the availability of marijuana may lure people away from prescription drugs, the researchers caution against drawing that conclusion too decisively. Factors specific to each state, such as attitudes about health, could explain the association between marijuana laws and overdose deaths, for example.
The researchers did, however, explore whether other policies targeting painkiller abuse -- such as having a drug-monitoring program or allowing pharmacists to ask for patient identification before dispensing medication -- were associated with declines in overdose death rates and did not find a significant connection.
Among the study's shortcomings is the fact that the researchers could not account for socioeconomic, racial, ethnic, medical or psychiatric differences among state populations.
But if further work can corroborate their findings, they wrote, enacting medical- marijuana laws could be promoted as part of a package of policies aimed at reducing painkiller abuse.