The claim that medical marijuana laws are linked to lower rates of fatal opioid overdoses may be wrong, according to a study published in PNAS.
A 2014 study published in JAMA Internal Medicine found states with medical marijuana laws saw slower increases in opioid overdose deaths between 1999 and 2010. The study's findings gained national attention and were widely cited by medical marijuana advocates, according to Vox.
The new study used the same methodology and data source as the 2014 study but includes figures through 2017. Researchers found states with medical marijuana laws experienced more opioid overdose deaths. These states saw a 22.7 percent increase in fatal overdoses between 1999 and 2017.
"We, the authors, think it's a mistake to look at that and say, 'Oh, cannabis was saving people 10 years ago, and it's killing people now," Chelsea Leigh Shover, PhD, lead study author and a postdoctoral research fellow at Stanford (Calif.) University, told Vox. "We think a more likely interpretation is that passing medical cannabis laws just is not affecting opioid deaths at the population level."