Cannabis and opioid overdoses: time to move on and examine potential mechanisms

Changes in Opioid and Benzodiazepine Poisoning Deaths After Cannabis Legalization in the US: A County-level Analysis, 2002-2020

BACKGROUND

Cannabis legalization for medical and recreational purposes has been suggested as an effective strategy to reduce opioid and benzodiazepine use and deaths. We examined the county-level association between medical and recreational cannabis laws and poisoning deaths involving opioids and benzodiazepines in the US from 2002 to 2020.

METHODS

Our ecologic county-level, spatiotemporal study comprised 49 states. Exposures were state-level implementation of medical and recreational cannabis laws and state-level initiation of cannabis dispensary sales. Our main outcomes were poisoning deaths involving any opioid, any benzodiazepine, and opioids with benzodiazepines. Secondary analyses included overdoses involving natural and semi-synthetic opioids, synthetic opioids, and heroin.

RESULTS

Implementation of medical cannabis laws was associated with increased deaths involving opioids (rate ratio [RR] = 1.14; 95% credible interval [CrI] = 1.11, 1.18), benzodiazepines (RR = 1.19; 95% CrI = 1.12, 1.26), and opioids+benzodiazepines (RR = 1.22; 95% CrI = 1.15, 1.30). Medical cannabis legalizations allowing dispensaries was associated with fewer deaths involving opioids (RR = 0.88; 95% CrI = 0.85, 0.91) but not benzodiazepine deaths; results for recreational cannabis implementation and opioid deaths were similar (RR = 0.81; 95% CrI = 0.75, 0.88). Recreational cannabis laws allowing dispensary sales was associated with consistent reductions in opioid- (RR = 0.83; 95% CrI = 0.76, 0.91), benzodiazepine- (RR = 0.79; 95% CrI = 0.68, 0.92), and opioid+benzodiazepine-related poisonings (RR = 0.83; 95% CrI = 0.70, 0.98).

CONCLUSIONS

Implementation of medical cannabis laws was associated with higher rates of opioid- and benzodiazepine-related deaths, whereas laws permitting broader cannabis access, including implementation of recreational cannabis laws and medical and recreational dispensaries, were associated with lower rates. The estimated effects of the expanded availability of cannabis seem dependent on the type of law implemented and its provisions.

Association of medical cannabis licensure with prescription opioid receipt: A population-based, individual-level retrospective cohort study

BACKGROUND

The endocannabinoid system has been implicated in physiological processes fundamental to pain, giving plausibility to the hypothesis that cannabis may be used as a substitute or complement to prescription opioids in the management of chronic pain. We examined the association of medical cannabis licensure with likelihood of prescription opioid receipt using administrative records.

METHODS

This study linked registry information for medical cannabis licensure with records from the prescription drug monitoring program from April 1, 2016 to March 31, 2019 to create a population-based, retrospective cohort in Rhode Island. We examined within-person changes in receipt of any opioid prescription and receipt of an opioid prescription with a morphine equivalent dose of 50 mg or more, and of 90 mg or more.

RESULTS

The sample included 5,296 participants with medical cannabis license. Medical cannabis licensure was not associated with the odds of filling any opioid prescription (OR: 0.99; 95% CI: 0.94-0.1.05) or the odds of filling a prescription with a morphine equivalent dose of 50 mg or more (OR: 0.93; 95% CI: 0.84-1.04) and 90 mg or more (OR: 0.99; 95% CI: 0.86-1.15).

CONCLUSION

Medical cannabis licensure was not associated with subsequent cessation and reduction in prescription opioid use. Re-scheduling of cannabis will allow for the conduct of randomized controlled trials to determine the efficacy of medical cannabis as an alternative to prescription opioid use or a complement to the use of lower doses of prescription opioids in patients with chronic pain.

The relationship between cannabis use and patient outcomes in medication-based treatment of opioid use disorder: A systematic review

Despite high rates of cannabis use during medication-based treatment of opioid use disorder (MOUD), uncertainty remains around how cannabis influences treatment outcomes. We sought to investigate the relationship between cannabis use during MOUD and a number of patient outcomes. We searched seven databases for original peer-reviewed studies documenting the relationship between cannabis use and at least one primary outcome (opioid use, treatment adherence, or treatment retention) among patients enrolled in methadone-, buprenorphine-, or naltrexone-based therapy for OUD. In total, 41 articles (including 23 methadone, 7 buprenorphine, 6 naltrexone, and 5 mixed modalities) were included in this review. For each primary outcome area, there was a small number of studies that produced findings suggestive of a supportive or detrimental role of concurrent cannabis use, but the majority of studies reported that cannabis use was not statistically significantly associated with the outcome. No studies of naltrexone treatment demonstrated significantly worse outcomes for cannabis users. We identified methodological shortcomings and future research priorities, including exploring the potential role of adjunct cannabis use for improving opioid craving and withdrawal during MOUD. While monitoring for cannabis use may help guide clinicians towards an improved treatment plan, cannabis use is unlikely to independently threaten treatment outcomes.

The costs and benefits of cannabis control policies

As is the case for most drugs, cannabis use has costs and benefits, and so do the policies that attempt to minimize the first and maximize the second. This article summarizes what we know about the harmful effects of recreational cannabis use and the benefits of medical cannabis use under the policy of prohibition that prevailed in developed countries until 2012. It outlines three broad ways in which cannabis prohibition may be relaxed, namely, the depenalization of personal possession and use, the legalization of medical use, and the legalization of adult recreational use. It reviews evidence to date on the impacts of each of these forms of liberalization on the costs and benefits of cannabis use. It makes some plausible conjectures about the future impacts of the commercialization of cannabis using experience from the commercialization of the alcohol, tobacco, and gambling industries. Cannabis policy entails unavoidable trade-offs between competing social values in the face of considerable uncertainty about the effects that more liberal cannabis policies will have on cannabis use and its consequences for better or worse.
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