The effect of cannabis laws on opioid use, J.L. Flexon et al., 2019

The effect of cannabis laws on opioid use.

J.L. Flexon, L. Stolzenberg, S.J. d’Alessio

International Journal of Drug Policy, 2019, 74, 152-159.

doi : 10.1016/j.drugpo.2019.09.013.



Many Americans rely on opioids at varying dosages to help ameliorate their suffering. However, empirical evidence is mounting that opioids are ineffective at controlling non-cancer related chronic pain, and many argue the strategies meant to relieve patient suffering are contributing to the growing opioid epidemic. Concurrently, several states now allow the use of medical cannabis to treat a variety of medical conditions, including chronic pain. Needing more exploration is the impact of cannabis laws on general opioid reliance and whether chronic pain sufferers are opting to use cannabis medicinally instead of opioids.


This study investigates the effect of Medical Marijuana Laws (MML)s on opioid use and misuse controlling for a number of relevant factors using data from several years of the National Survey on Drug Use and Health and multivariate logistic regression and longitudinal analysis strategies.


Results provide evidence that MMLs may be effective at reducing opioid reliance as survey respondents living in states with medical cannabis legislation are much less apt to report using opioid analgesics than people living in states without such laws, net other factors. Results further indicate that the presence of medicinal cannabis legislation appears to have no influence over opioid misuse.


MMLs may ultimately serve to attenuate the consequences of opioid overreliance.



While numbers vary, it is estimated that up to 116 million Americans suffer from chronic pain (Institute of Medicine, 2011; Reuben et al., 2015), with concentration in the older adult population (> 40%) (Johannes, Le, Zhou, Johnston & Dworkin, 2010; Volkow & McLellan, 2016). Of this group, an estimated 5 to 8 million Americans needing long-term pain management (Reuben et al., 2015), or roughly between 8% to 30%, rely on opioids at varying dosage levels (Nuckols et al., 2014). Although opioids were originally reserved for patients with cancer-related pain, post-operative pain, and for patients needing palliative care, state medical boards over the past two decades have eased laws regulating the granting of opioid prescriptions. This loosening of opioid prescription laws has contributed to a dramatic rise in the public’s use of opioids making it the most often prescribed analgesic in the U.S. (Volkow & McLellan, 2016). To illustrate, the issuance of opioid prescriptions increased from 76 million in 1991 to 219 million by 2011 (Reuben et al., 2015), and by 2014, 245 million prescriptions for opioids were dispensed from U.S. pharmacies not accounting for refills (National Institute on Drug Abuse, 2015; Volkow & McLellen, 2016). This trend clearly parallels the movement by the medical community to manage chronic pain and lessen patient suffering. Further contributing to the widespread use of opioids is that there are few alternatives to deal with chronic pain, the recognition that patients have an endemic right to pain relief, advocacy by support organizations to use opioids, and the aggressive marketing by pharmaceutical companies (Manchikanti et al., 2012; Volkow & McLellan, 2016).

Reliance on opioids is not without detriment. Opioid use has an associated cost of $560–635 billion in reduced work productivity, sick time, medication expenses, and medical care (Institute of Medicine, 2011; Reuben et al., 2015). Hospital visits for problematic opioid use are now quite common. Between the years of 2005 to 2014, opioid related emergency room visits increased 117% and associated hospital stays increased by 76% (Mallow, Belk, Topmiller & Strassels, 2018). Deaths attributable to prescription opioid overdose rose from 3442 in 1999 to 17,029 in 2017, and drug overdose deaths from any opioid use rose from 8048 to 47,600 during the same time period (National Institute on Drug Abuse, 2019). Recent projections indicate that opioid overdoses will worsen with an annual number of deaths reaching approximately 82,000 by 2025, yielding a total of over 700,000 projected deaths between 2016 and 2025 (Chen et al., 2019). It is striking that 80% of these deaths were attributable to illicit use, and problematically these researchers only found modest impact on these projections from alterations in prescribing behaviour, such as strategies meant to prevent prescription opioid misuse. Alarmingly, “.. opioid analgesics are now responsible for more deaths than the number of deaths from both suicide and motor vehicle crashes, or deaths from cocaine and heroin combined” (Manchikanti et al., 2012, p. ES9). Contributing to the problem is a belief among the public that prescription drugs are safer to misuse than illicit drugs along with a related tendency to use opioids with other drugs such as benzodiazepines (Nuckols et al., 2014). Both of these behaviours, and others, may be in response to inadequate pain control and can ultimately contribute to increased morbidity and mortality.

The widespread reliance on opioids to manage patient suffering appears to be nested in tradition, clinical experience, and anecdotal observations rather than on sound, empirically-based evidence (Manchikanti et al., 2012). There is no corroboration of a long-term benefit in either chronic pain or function stemming from treatment with opioids, but rather increased harms including problematic substance
use, opioid use disorder, overdose, and motor vehicle injury are quite possible (Dowell, Haegerich & Chou, 2016). To illustrate, a comprehensive review of the extant literature undertaken by Martell et al. (2007) not only failed to discern any indication that opioid use mollified chronic back pain, but there was also evidence of significant substance use disorder along with aberrant medicationtaking behaviours in as high as 24% of the opioid patients. Further, the Center for Disease Control (CDC) reports that alternative therapies in the forms of nonpharmacologic (e.g., exercise) and nonopioid therapy (e.g., NSAIDS, acetaminophen) have been shown to cause less harm and show more efficacy in pain management, and the new recommendation is that nonopioid treatment is preferred for chronic pain.