A paper written nearly five years ago launched hopes that medical marijuana could help fight the opioid epidemic. If more people used the less addictive and less harmful pot instead of opioids, the thinking went, deaths might abate.But a new paper, published today in the Proceedings of the National Academy of Sciences, throws cold water on that dream. A new set of researchers replicated part of the 2014 study’s findings: That is, from 1999 to 2010, it’s true that the introduction of medical-marijuana laws was associated with a decline in opioid-overdose deaths. But when the researchers included states that introduced laws between 2010 and 2017, the direction of the relationship reversed. Instead of a reduction in opioid overdoses, medical marijuana was associated with a 23 percent increase in overdose deaths. Read more..