The enactment of medicinal marijuana laws is associated with significantly lower state-level opioid overdose mortality rates, according to data published online today in the Journal of the American Medical Association (JAMA) Internal Medicine.
A team of investigators from the University of Pennsylvania, the Albert Einstein College of Medicine in New York City, and the Johns Hopkins Bloomberg School of Public Health in Baltimore conducted a time-series analysis of medical cannabis laws and state-level death certificate data in the United States from 1999 to 2010 — a period during which 13 states instituted laws allowing for cannabis therapy.
Researchers reported, “States with medical cannabis laws had a 24.8% lower mean annual opioid overdose mortality rate compared with states without medical cannabis laws.” Specifically, overdose deaths from opioids decreased by an average of 20 percent one year after the law’s implementation, 25 percent by two years, and up to 33 percent by years five and six.
They concluded, “In an analysis of death certificate data from 1999 to 2010, we found that states with medical cannabis laws had lower mean opioid analgesic overdose mortality rates compared with states without such laws. This finding persisted when excluding intentional overdose deaths (ie, suicide), suggesting that medical cannabis laws are associated with lower opioid analgesic overdose mortality among individuals using opioid analgesics for medical indications. Similarly, the association between medical cannabis laws and lower opioid analgesic overdose mortality rates persisted when including all deaths related to heroin, even if no opioid analgesic was present, indicating that lower rates of opioid analgesic overdose mortality were not offset by higher rates of heroin overdose mortality. Although the exact mechanism is unclear, our results suggest a link between medical cannabis laws and lower opioid analgesic overdose mortality.”
In a written statement to Reuters Health, lead author Dr. Marcus Bachhuber said: “Most of the discussion on medical marijuana has been about its effect on individuals in terms of reducing pain or other symptoms. The unique contribution of our study is the finding that medical marijuana laws and policies may have a broader impact on public health.”
Added co-author Colleen L. Barry in USA Today: “[The study's findings] suggest the potential for many lives to be saved. … We can speculate … that people are completely switching or perhaps supplementing, which allows them to lower the dosage of their prescription opioid.”
Nationwide, overdose deaths involving opioid analgesics have increased dramatically over the past decade. While fewer than 4,100 opiate-induced fatalities were reported for the year 1999, by 2010 this figure rose to over 16,600 according to an analysis by the US Centers for Disease Control.
An abstract of the JAMA study, “Medical Cannabis Laws and Opioid Analgesic Overdose Mortality in the United States, 1999-2010,” appears online here.