Drivers in states allowing medical marijuana use are less likely to test positive for opioids after fatal vehicular crashes, according to a study by Columbia University’s Mailman School of Public Health.
The report, published in the American Journal of Public Health, evaluated Fatality Analysis Reporting System data from 1999 to 2013. States, such as Colorado, that permit medical marijuana use saw fewer opioid-involved accidents than those that did not allow its use, the study found.
“This study is about the possible substitution relationship between marijuana and opioids,” senior author Dr. Guohua Li, Mailman School professor of epidemiology, said in a press release.
The data included nearly 68,400 deceased drivers. Forty-two percent of these individuals died in states that had passed a medical marijuana law. This included 18 states that tested for drugs and alcohol in at least 80 percent of drivers who died within an hour of crashing.
Individuals aged 21–40 saw the greatest reduction in opioid-involved crashes. This decline could be attributed to age restrictions: many states require medical marijuana users be at least 21 years old, and most patients are younger than 45.
The study’s authors anticipate similar reductions in opioid use among older groups if the acceptance of medical marijuana continues to spread.
The study is one of the first to assess the link between medical marijuana laws and opioid use at an individual level. The findings come nearly five weeks after the U.S. Drug Enforcement Administration refused to remove cannabis from its list of Schedule I substances.
Lead author June H. Kim, a doctoral student in the Department of Epidemiology at the Mailman School of Public Health, found the results unsurprising. He suggested that many individuals in marijuana-friendly states treat chronic pain with cannabis rather than opioids.
Previous studies also indicate that weed may be used in lieu of prescription painkillers to relieve chronic pain.
A 2015 study published in The Journal of the American Medical Association evaluated the pharmacology of medical marijuana use based on medical literature spanning from 1948 to 2015. The results found that cannabis use was effective in reducing chronic and neuropathic pain.
Another study, published in the journal Health Affairs, indicated that states with legalized medical marijuana experienced declines in the amount of Medicare prescriptions used to treat chronic pain, anxiety or depression. These drugs may include Vicodin, Xanax or Prozac.
“Our findings and existing clinical literature imply that patients respond to medical marijuana legislation as if there are clinical benefits to the drug, which adds to the growing body of evidence suggesting that the Schedule I status of marijuana is outdated,” the study’s authors concluded.
Numerous states will have a marijuana-related measure on ballot this November.
Voters in five states will vote to legalize the drug for recreational use. These states include Arizona, California, Maine, Massachusetts and Nevada.
Arkansas, Florida, Montana and North Dakota will decide whether to legalize the use of medical marijuana.
Currently, 25 states and the District of Columbia allow some form of cannabis use.
Colorado legalized the use and possession of marijuana in 2012. A March 2016 report found that marijuana use among Colorado adults aged 18–25 increased from 21 percent in 2006 to 31 percent in 2014. Also, marijuana-related arrests in the state fell by 46 percent from 2012 to 2014.
The DEA has yet to report a marijuana-related overdose death. Conversely, the Centers for Disease Control and Prevention say opioids, including heroin, killed more than 28,000 people in 2014, more than any year on record.