Study: Medical marijuana may not help alleviate opioid crisis

States that have legalized medical marijuana have seen more opioid overdose deaths, according to a new study reported on by Vox — the opposite of what a 2014 study found.

The state of play: The previous study suggested that when people could use cannabis to treat pain instead of opioids, it led to less overdoses. It was embraced by some state lawmakers. However, the researchers who conducted the latest study say that there's probably no relationship between state marijuana laws and opioid deaths.

Go deeper: The states using medical marijuana for opioid substitutes