By Dennis Thompson
The studies couldn't prove cause and effect. But one study found that opioids dispensed through Medicare's prescription drug plan decreased significantly if people had access to medical pot dispensaries or were allowed to grow marijuana for their own use.
"We had about a 14.5 percent reduction in opiate use when states turned on dispensaries, and about a 7 percent reduction in opiate use when states turned on home cultivation-based cannabis laws," said researcher David Bradford, chairman of public policy at the University of Georgia School of Public and International Affairs.
The other study, led by researcher Hefei Wen, from the University of Kentucky College of Public Health, found a decrease in opioid prescriptions covered by Medicaid in states that legalized either medicinal or recreational pot.
Both types of laws were linked to about a 6 percent decline in opioid prescribing, researchers reported.
"We do think there's good reason to be hopeful that cannabis might be one tool out of many we could use to address the opioid epidemic," Bradford said.
Drug overdoses killed nearly 64,000 Americans in 2016, with two-thirds of deaths involving a prescription or illicit opioid, the U.S. Centers for Disease Control and Prevention reported last week. Overdose deaths rose 21.5 percent in 2016, a much sharper spike than the 11.4 percent increase seen the previous year.
At this point, 30 states and the District of Columbia have laws legalizing some form of marijuana use, including eight states that have legalized recreational use.
Studies have found medical pot is effective in treating chronic pain, Bradford said. In 2017, the prestigious National Academies of Sciences, Engineering and Medicine issued a report concluding that pot can significantly reduce pain symptoms.
Both research teams suspected that if this were true, then medical marijuana might ease opioid use in people with chronic pain.
To investigate this theory, the investigators turned to recent data from the federal insurance programs Medicare and Medicaid. They compared opioid prescribing patterns between states with medical or recreational pot and those that have taken a hard line against weed.
An average state filled 23 million daily doses of opioids through Medicare's prescription drug plan between 2010 and 2015, Bradford's team found.
But states with medical pot dispensaries filled 3.7 million fewer daily doses, and states with home cultivation filled 1.8 million fewer doses, they said.
Results did vary based on the type of opioid, however. Medical pot was linked to reductions in hydrocodone, morphine and fentanyl prescriptions, but not to prescriptions for oxycodone, Bradford said.
The second study found a similar effect among people covered by Medicaid.
The two studies were published online April 2 in JAMA Internal Medicine.
"I think at this point, with patients dying every day as a result of opioid use disorder, we need to consider all possible solutions to the crisis," said Dr. Kevin Hill, director of addiction psychiatry at Beth Israel Deaconess Medical Center in Boston and an assistant professor of psychiatry at Harvard Medical School. "Papers like these two suggest that cannabis may play a role."
He said these studies and others offer strong support for anecdotal evidence from patients who report they need fewer opioids for chronic pain when they are put on medical cannabis. Hill wrote an editorial that accompanied the two articles.
At the same time, Hill says medical marijuana should not be given a lead role in treating chronic pain. Instead, it should be a back-up option for patients who are struggling to manage pain and who could be in danger of addiction.
"I think it's hard to deny that there is a growing body of evidence that suggests a role for cannabis in treating chronic pain, but it's not the level where it would be a first-line or even second-line treatment," Hill said.