Editorial Note: This study, originally published in the Journal of American Medical Association earlier this year is one of two recent studies examining the impact state cannabis regulation has had on opiate prescriptions written by health care providers each year. This study quantifies data having to do with the rate of which opiate prescriptions filled by Medicaid recipients over a period of 15 years in states that regulate medical marijuana and/or adult-use cannabis.
Key Points
Question Are medical and adult-use marijuana laws passed after 2010 associated with lower rates of opioid prescribing for Medicaid enrollees?
Findings In this population-based, cross-sectional study using the all-capture Medicaid prescription data for 2011 to 2016, medical marijuana laws and adult-use marijuana laws were associated with lower opioid prescribing rates (5.88% and 6.38% lower, respectively).
Meaning Medical and adult-use marijuana laws have the potential to lower opioid prescribing for Medicaid enrollees, a high-risk population for chronic pain, opioid use disorder, and opioid overdose, and marijuana liberalization may serve as a component of a comprehensive package to tackle the opioid epidemic.
Abstract
Importance Overprescribing of opioids is considered a major driving force behind the opioid epidemic in the United States. Marijuana is one of the potential nonopioid alternatives that can relieve pain at a relatively lower risk of addiction and virtually no risk of overdose. Marijuana liberalization, including medical and adult-use marijuana laws, has made marijuana available to more Americans.
Objective To examine the association of state implementation of medical and adult-use marijuana laws with opioid prescribing rates and spending among Medicaid enrollees.
Design, Setting, and Participants This cross-sectional study used a quasi-experimental difference-in-differences design comparing opioid prescribing trends between states that started to implement medical and adult-use marijuana laws between 2011 and 2016 and the remaining states. This population-based study across the United States included all Medicaid fee-for-service and managed care enrollees, a high-risk population for chronic pain, opioid use disorder, and opioid overdose.
Exposures State implementation of medical and adult-use marijuana laws from 2011 to 2016.
Main Outcomes and Measures Opioid prescribing rate, measured as the number of opioid prescriptions covered by Medicaid on a quarterly, per-1000-Medicaid-enrollee basis.
Results State implementation of medical marijuana laws was associated with a 5.88% lower rate of opioid prescribing (95% CI, −11.55% to approximately −0.21%). Moreover, the implementation of adult-use marijuana laws, which all occurred in states with existing medical marijuana laws, was associated with a 6.38% lower rate of opioid prescribing (95% CI, −12.20% to approximately −0.56%).
Conclusions and Relevance The potential of marijuana liberalization to reduce the use and consequences of prescription opioids among Medicaid enrollees deserves consideration during the policy discussions about marijuana reform and the opioid epidemic.
Introduction
Overprescribing of opioids for pain management is considered a major driving force behind the opioid epidemic in the United States1,2 A concerted policy effort has been made during the past decade to regulate opioid-prescribing practices.3 As access to prescription opioids becomes increasingly restricted, there is growing concern that restrictions on prescription opioids may have pushed those already addicted to opioids to seek more dangerous drugs and sources.4
The potential unintended consequences of restricting access to prescription opioids has shifted some policy attention to the development and use of nonopioid alternatives.5,6 Marijuana is one of the potential alternative drugs that can provide relief from pain at a relatively lower risk of addiction and virtually no risk of overdose.7–9 The therapeutic value of marijuana has been one of the central rationales behind the marijuana liberalization policies in many states that now allow marijuana use for medical and adult-use purposes.10 On the one hand, proponents of these medical and adult-use marijuana laws tout marijuana liberalization as a potential solution to the excessive use of opioids.5,6,10 Some opponents, on the other hand, view marijuana as a “gateway” or “stepping stone” to opioids and worry that marijuana liberalization may exacerbate the opioid epidemic.6,11
Although both medical and adult-use marijuana laws, in principle, have made marijuana available to more Americans, the laws targeted different groups and may have different opioid-related consequences. In medical marijuana laws, states typically specify a list of conditions that are eligible for medical marijuana, and most states have included in the list generic terms such as “severe pain,” “chronic pain,” or “intractable pain unrelieved by standard medical treatment and medications.” Patients with eligible conditions are expected to obtain recommendation from qualified physicians and enroll in a patient registry. Patients are then issued identification cards that allow them or their caregivers to possess a certain amount of marijuana through home cultivation and licensed dispensaries (in some states these are called “compassionate centers”).10 As a result, medical marijuana laws may have affected pain management for only a selected group of patients with pain and with state-specified eligible conditions, sources of care from licensed marijuana physicians, and ready access to marijuana.
Adult-use marijuana laws, which to date have been enacted only in states with existing medical marijuana systems, fundamentally restructured the distribution and possession of marijuana. Unlike the eligibility criteria and registry and/or renewal process under medical marijuana laws, adult-use marijuana laws permit all adults 21 years or older to use marijuana. Furthermore, marijuana supply channels have often been expanded through grow operations and retail dispensaries licensed and taxed by the states.10 Thus, adult-use marijuana laws enable individuals without eligibility or access to medical marijuana before such laws to use marijuana as self-medication for pain conditions. A potential repercussion of adult-use marijuana laws, however, is that the outright legalization/taxation message conveyed by the laws may encourage individuals to normalize the risky behaviors in general.12
Empirical studies on medical marijuana laws have indicated downstream policy effects on reducing opioid-related hospitalizations, opioid overdose deaths, and opioid-involved traffic fatalities.5,13,14 Furthermore, Bradford and Bradford15,16found evidence that the implementation of medical marijuana laws reduced the number of prescriptions used to treat the conditions, including pain, which most states have deemed eligible for medical marijuana. However, the authors did not single out prescription opioids. The prescription opioids were aggregated with nonopioid analgesics and 9 other classes of drugs broadly classified as pain-related prescriptions (eg, antidepressants, muscle relaxants, respiratory inhalant products, functional bowel disorder agents).
Regarding adult-use marijuana laws, only 1 study to date has examined the policy effect on opioid-related health outcomes. Livingston and colleagues17 found an interrupted reversal of the upward trend in Colorado’s opioid overdose mortality when the state legalized adult-use marijuana use. No study to date has focused on the effect of medical and adult-use marijuana laws on opioid prescribing in particular.
We examined the opioid prescribing rates among Medicaid enrollees in the context of state marijuana liberalization policies between 2011 and 2016. During this period, an estimated one-third of opioid prescriptions were misused or abused, of which Medicaid shared a disproportionately large burden.18 In addition to opioid prescribing rates, we also studied Medicaid spending on prescription opioids, as well as the prescribing rates of, and spending on, nonopioid pain medications. As medical and adult-use marijuana laws continue to gather momentum in state legislatures, the study findings are informative for states’ implementation and iterations of marijuana reform as well as the nation’s fight against the opioid epidemic.
Citation
Bradford AC, Bradford WD, Abraham A, Bagwell Adams G. Association Between US State Medical Cannabis Laws and Opioid Prescribing in the Medicare Part D Population. JAMA Intern Med. Published online April 02, 2018. doi:10.1001/jamainternmed.2018.0266
