During the past two decades, more than half of U.S. states implemented policies that legalizes marijuana use for medical purposes.
Researchers have been studying the health ramifications of this sweeping public policy decision. Now, NIDA-supported researchers have found that providing legal and practical access to marijuana may have positive impacts on opioid use. Economists Dr. David Powell and Dr. Rosalie Pacula at the RAND Corporation, in Santa Monica, California, and Dr. Mireille Jacobson at the University of California, Irvine (UC-I) studied three medical marijuana policies. They found that the policies, despite their common motivation, have had varied, and sometimes offsetting, indirect effects on substance use and related problems. The most striking finding was that legally protected marijuana dispensaries (LMDs) were associated with lower rates of dependence on prescription opioids, and deaths due to opioid overdose, than would have been expected based on prior trends.
The Opioid Connection
During the study period (between 2004 and 2014), seventeen states provided legal protection to dispensaries. In these states, patients who meet eligibility requirements for medical marijuana had ready and safe access to the drug. In contrast, patients in states that allowed doctors to recommend marijuana but did not have LMDs may have turned to illicit or quasi-illicit sources, and feared legal jeopardy, to obtain the drug. Dr. Powell and his co-investigators compared rates of opioid-related treatment admissions and mortality rates in states with and without LMDs using data from the annually compiled Treatment Episodes Data Set (TEDS) and the National Vital Statistics System, respectively. Their analysis revealed that states with LMDs had lower opioid-overdose mortality rates and fewer admissions to treatment for opioid addiction than they would have had without the dispensaries. The estimated sizes of the reductions were 16-3% in mortality due to prescription opioid overdoses, and 28-35% in admissions for treatment of opioid addiction. This latter reduction was steeper, up to 53%, among patients who entered treatment independently of the criminal justice system. The researchers also noted a trend whereby the longer LMDs were in place, the more the incidence of opioid-related problems declined.
To account for these findings, the RAND/UC-I team speculates that some patients with chronic pain may find that marijuana affords valuable analgesia with more acceptable side effects than opioids. LMDs will make it easier for such patients to obtain and use marijuana, and so reduce their reliance on opioids to manage their pain. Another possible explanation, the researchers suggest, is that where LMDs exist, recreational drug users may find marijuana simpler and less risky to divert than prescription opioids. Both scenarios could reduce a population’s exposure to opioid medications and the associated problems of overdose and addiction.