Introduction
The opioid epidemic in America is being driven by overprescription of opioids for pain management. A concerted effort was made to regulate opioid prescribing practices during the past decade. There is increasing concern that opioid-addicts might have turned to more dangerous and difficult drugs as their access to prescription opioids becomes less available.
Some policy attention has been shifted to nonopioid alternative development and use due to the potential unintended effects of restricting prescription opioid access. Marijuana, which can be used to relieve pain and has a low risk of addiction and almost no chance of overdose, is one potential alternative drug. Many states have now legalized marijuana for adult and medical use. This is largely due to the therapeutic benefits of marijuana. Proponents of the adult-use and medical marijuana laws see marijuana liberalization as a solution to excessive opioid use. Opponents, on the contrary, see marijuana as a "gateway" to opioids. They fear that marijuana liberalization could worsen the opioid crisis.
While both adult-use and medical marijuana laws have in principle made marijuana more accessible to Americans, they targeted different groups and could have different opioid-related consequences. The state's medical marijuana laws usually include a list of qualifying conditions. Most states have included generic terms like "severe pain", "chronic pain" or "intractable, unrelieved pain without standard medical treatment and medication." Patients with these conditions will need to get a recommendation from qualified doctors and register in a patient registry. The identification cards allow patients or their caregivers to possess certain amounts of marijuana via home cultivation or licensed dispensaries (in other states, these are called "compassionate centres"). Medical marijuana laws could have had an impact on pain management for a small number of patients who are suffering from pain.
The adult-use marijuana laws have fundamentally changed the way marijuana is distributed and possessed. They were only enacted in states that already had medical marijuana systems. Adult-use marijuana laws allow anyone 21 years old or older to possess marijuana, unlike the eligibility criteria and renewal process for medical marijuana laws. Additionally, grow operations and retail dispensaries that are licensed and taxed in the states have helped expand marijuana supply. Adult-use marijuana laws allow individuals who are not eligible or have no access to medical marijuana to use marijuana for self-treatment of pain conditions. However, adult-use marijuana laws could have a negative impact on people's willingness to accept risky behavior in general due to the fact that they are outright legalization/taxation messages.
Studies on the effects of medical marijuana laws on opioid-related hospitalizations and deaths from overdoses have shown that there are downstream policy impacts on opioid-related traffic fatalities, as well as opioid-related deaths. Bradford and Bradford also found evidence that medical marijuana laws had a positive effect on the number of prescriptions for treating the conditions. This includes pain. Most states are eligible for medical cannabis. The authors didn't mention prescription opioids. The prescription opioids were combined with nonopioid painkillers and 9 other drugs that are broadly considered to be pain-related prescriptions (eg antidepressants/muscle relaxants/respiratory inhalant products, functional intestinal disorder agents).
Only 1 study has been done to date on the impact of adult-use marijuana laws on opioid-related outcomes. Livingston and his colleagues discovered an abrupt reversal in the trend of opioid overdose deaths in Colorado after legalization for adult-use marijuana. There has been no study that specifically examined the impact of marijuana laws on opioid prescribing.
Methods
Data
This study was not subject to institutional review board review. This study used the State Drug Utilization Data (CMS) as its primary data source. Each state is required to submit quarterly reports to CMS on the total outpatient drug prescriptions that are covered by Medicaid fee for service and managed care, in exchange to federal matching funds. Due to inconsistent reporting by states, we excluded some observations from the study data. The study sample contains 1059 observations from each state quarter.
Data were used from the first quarter 2011 through the second quarter 2016. 2011 was the first year that mandatory reporting by states of Medicaid managed care prescription data was implemented. This is also the first year the Affordable Care Act (ACA data collection requirements) made it almost complete. Many high-risk, low-income adults who have recently enrolled in Medicaid under the expansion provisions or Section 1115 waiver are included in the managed care data. The recent expansion revealed that these low-income adults have high risk for chronic pain and opioid overdose. We chose the study window because it minimizes the impact of certain national policies and guidelines, which were either in place in 2011 or about to be published in 2016. These common changes include the 2010 OxyContin Reformulation, publication of 2 national guidelines for opioid prescribing in chronic Pain management in 2009 and 2010, and the warning letter from the Surgeon General about the opioid crisis in 2016.
Results
The In shows that states that have implemented medical and adult-use cannabis laws had lower Medicaid-covered opioid prescribing rates. The implementation of medical marijuana laws resulted in a 5.88% decrease in Medicaid-covered opioid prescriptions (95%CI, -11.55% up to approximately -0.21%). The annual rate of Medicaid-covered prescriptions for opioids is 670.16 per 1000 people in states that have medical marijuana laws. This means that medical marijuana laws will result in 39.41 fewer prescriptions per 1,000 people per year. Additionally, states that have medical marijuana laws also implemented adult-use cannabis laws saw an additional 6.38% decrease in opioid prescriptions (95% confidence interval, -12.20% to about -0.56%). The annual average of states that have medical marijuana laws and no adult-use cannabis laws (i.e. 621.82 opioid prescribing per 1000 enrollees) can show the effect size. This is 39.67 fewer prescriptions per 1,000 enrollees annually. The lower opioid prescribing rate due to adult-use marijuana laws was concentrated in Schedule II opioids (-7.79%, 95%CI, -14.73% – approximately -0.85%), while the lower prescribing rates associated with medical marijuana laws were more prominent in Schedule III and V opioids (10.40%; 95%CI, -19.05% – approximately -1.74%).
This report presents a more complex picture of state-specific policy impacts. The opioid prescribing rate in Delaware, Massachusetts and Minnesota was significantly lower than in the other 8 states that implemented medical marijuana laws. However, the possible differences in prescribing rates between New Hampshire and Illinois were not accurately estimated. However, Connecticut and Maryland did not experience statistically significant or clinically discernable increases in opioid prescribing rates as a result of the implementation medical marijuana laws.
Concerning adult-use cannabis states, 3 out of 4 (i.e. Alaska, Colorado, Oregon) had significantly lower opioid prescribing rate associated with the implementation adult-use pot laws. Washington's change was moderate.
Additionally, adult-use marijuana laws were associated with a 9.78% decrease in Medicaid spending on prescription opioids (95%CI, -18.29% – approximately -1.26%), which is equivalent to $1815 per 1000 Medicaid enrollees. Additionally, the implementation of adult-use marijuana laws had a lower rate for Medicaid-covered prescriptions of nonopioid pain medication, 8.36% (95%CI, -13.67% – approximately -3.05%), and 8.69% (95%CI, 15.50% – approximately -1.89%), respectively.
The main findings were confirmed by the results of sensitivity analyses. The validity of the methods was further supported by the falsification and "parallel-trend assumption", tests.
Discussion
This study is the first to show that Medicaid-covered opioid prescribing and spending decreased between 2011 and 2016. These findings are in line with Bradford and Bradford's, who also found a reduction in the broad category of prescriptions for pain that were covered by Medicaid due to medical marijuana laws. In the current context of the opioid crisis, it is crucial to focus on opioids. We also discovered that adult-use marijuana laws were associated with lower opioid prescribing rates, something we had not previously investigated.
Patients with valid prescriptions for pain management from their doctors were at the forefront of opioid abuse disorder and overdose cases. These patients may have been able to access marijuana and legal protection because they had the option of using it as a pain relief alternative. According to the 2017 Yahoo News/Marist Poll 83% of Americans support legalizing marijuana for medical purposes. For years to come, more states will have medical marijuana laws. This could help reduce prescription opioid use in pain management. It may also decrease opioid overdose and opioid use disorder. Evidence suggests that marijuana may be able to ease withdrawal symptoms. Thus, legalizing marijuana could reduce prescription opioid use on two fronts. It can serve as a replacement for opioid pain medication and as an addition to treatment for opioid use disorder.
We found 2 states, Connecticut, and Maryland, in which the state's medical marijuana laws had a much lower impact on prescriptions of opioids. These 2 exceptions could have several possible causes. First, Connecticut didn't list any pain conditions that were eligible for medical marijuana in the study period. In fact, it only included "complex regional pain syndrome" which is a rare chronic condition. This was one of the extended eligible conditions added in late 2016. A second reason Maryland didn't have an operating medical marijuana system in place by the end of 2016 was multiple legal disputes and bureaucratic hurdles.
It is worth noting that adult-use marijuana laws are associated with lower prescription opioid rates and spending. The fact that adult-use cannabis laws were in effect in all states before the introduction of adult-use laws suggests that some individuals may not be able to access medical marijuana laws and could also benefit from marijuana as an alternative to opioids. The fact that opioid prescribing rates for adult-use marijuana laws were lower than those for Schedule II opioids further suggests that reaching these people may be more effective in reducing the negative consequences of opioid overdose and opioid addiction. A record 64% support adult-use marijuana laws according to a Gallup poll. Only four of the five ballot initiatives for adult use marijuana were approved by the 2016 Election Day. 2018 may see more states adopting medical marijuana laws vote on adult-use cannabis bills. Consider the potential for adult-use marijuana laws in order to decrease the use of and the consequences of addictive opioids, particularly in states that have been hard hit by the opioid crisis. The states that are reluctant to legalize adult-use marijuana or those who debate medical marijuana can still make policy efforts to expand the availability of cannabis to all people.
