Legalizing medical marijuana no longer appears to be linked with a drop in fatal opioid overdoses, according to a new U.S. study that calls into question the potential for cannabis to help fix the opioid crisis.
In recent years, many advocates for legalizing marijuana - including some doctors and public health officials - have cited a pivotal 2014 study that found lower rates of fatal opioid overdoses from 1999 to 2010 in the states that legalized medical marijuana.
For the current study, published in the Proceedings of the National Academy of Sciences, researchers used similar methods to take another look at the same period examined in the 2014 study and extend the analysis through 2017, to include many states that only recently legalized medical marijuana.
The new study found a similar result for the same period covered in that 2014 study: about a 21 percent decrease in opioid overdose deaths for every 100,000 people in the population when states legalized medical marijuana.
But when the new study looked over more time - from 1999 to 2017 - they found an almost 23 percent increase in opioid overdose deaths in states with medical marijuana laws.