Frequent Cannabis Use and Cessation of Injection of Opioids, Vancouver, Canada, 2005-2018

Cannabis use and illicit opioid cessation among people who use drugs living with chronic pain

INTRODUCTION

Amidst the opioid overdose crisis, there is interest in cannabis use for pain management and harm reduction. We investigated the relationship between cannabis use and cessation of unregulated opioid use among people who use drugs (PWUD) living with chronic pain.

METHOD

Data for analyses were collected from three prospective cohort studies in Vancouver, Canada. All cohort participants who completed at least two study visits and reported both pain and unregulated opioid use in the past 6 months were included in the present study. We analysed the association between cannabis use frequency and opioid cessation rates using extended Cox regression models with time-updated covariates.

RESULTS

Between June 2014 and May 2022, 2340 PWUD were initially recruited and of those 1242 PWUD reported chronic pain, use of unregulated opioids and completed at least two follow-up visits. Of these 1242 participants, 764 experienced a cessation event over 1038.2 person-years resulting in a cessation rate of 28.5 per 100 person-years (95% confidence interval [CI] 25.4-31.9). Daily cannabis use was positively associated with opioid cessation (adjusted hazard ratio 1.40, 95% CI 1.08-1.81; p = 0.011). In the sex-stratified sub-analyses, daily cannabis use was significantly associated with increased rates of opioid cessation among males (adjusted hazard ratio 1.50, 95% CI 1.09-2.08; p = 0.014).

DISCUSSION AND CONCLUSIONS

Participants reporting daily cannabis use exhibited higher rates of cessation compared to less frequent users or non-users. Observed sex-specific differences in cannabis use and opioid cessation suggest potential differences in cannabis use behaviours and effects. Our findings add to the growing evidence supporting the potential benefits of cannabis use among PWUD, underlining the need for further research.

Cannabis retail store density and county-level mortality from injury in the state of Washington from 2009-2020

Background: The state of Washington legalized cannabis for adult use in 2012 and retail stores began to open in 2014 with 31 stores, rising to 447 in 2020. Prior studies have evaluated impacts of legalization on state-level mortality from suicide, motor vehicle accidents and opioid poisonings with mixed findings.Objectives: To estimate relationships between county cannabis retail store density and county mortality rates from suicide, motor vehicle accidents, opioid poisoning, homicide and accidental poisonings.Methods: County mortality data for Washington state (39 counties) from individual death records for the years 2009-2020 used ICD-10 Multiple Cause of Death Files. County-level cannabis retail store counts in Washington were based on cannabis license and sales data. Fixed effect Poisson regression models predicted county-level yearly mortality rates for 2009-2020.Results: Deaths from 2009-20 in Washington were 12,933 (77% men) from suicide, 6761 (71% men) from motor vehicle accidents, 8858 (62% men) from opioid poisoning, 2408 (73% men) from homicide and 11,873 (64% men) from accidental poisonings. Store counts per 10,000 population were negatively associated with accidental poisonings (incidence rate ratio (IRR) of 0.83 (0.73-0.93)) and opioid mortality rates with (IRR of 0.83 (0.70-0.99)). No significant effects were found for motor vehicle accidents, homicide or suicide.Conclusions: County cannabis retail store density in Washington was associated with reduced accidental poisoning and opioid mortality while suicide and motor vehicle accident mortality rates did not appear to change. Results do not support any harmful effects on mortality from cannabis store expansion in Washington counties.

"Smoking weed it gets you over the hump": Cannabis co-use as a facilitator of decreased opioid use among people who inject drugs in Los Angeles, California

Introduction

Opioid overdose mortality rates have surged dramatically in the last decade due largely to fentanyl in the illicit US drug supply. As of June 2024, 38 states, three territories, namely US Virgin Islands, Guam and the Northern Mariana Islands, and the District of Columbia, allow the medical use of cannabis products. However, there remains limited qualitative community-based evidence on the role of cannabis co-use among opioid using and injecting populations. In this study, we present data from people who inject drugs (PWID)'s co-use of cannabis-opioid.

Methods

We conducted 30 one-on-one semi-structured interviews with PWID from July 2021 to April 2022 at two community sites in Los Angeles, CA, near a syringe service program and a methadone clinic. Interviews were recorded and transcribed. We used constructivist grounded theory methods for identifying and comparing the emerging themes that appeared across transcripts to construct a conceptual explanation of how PWID co-used cannabis and opioids. Participant inclusion criteria included injection drug use, opioid and cannabis use, English fluency, and age 18+ years.

Results

PWID described that cannabis co-use assisted in developing patterns of reduced opioid use in a number of ways: 1) maintain opioid cessation and/or adhere to opioid use disorder treatment by managing cessation-specific symptoms, 2) manage symptoms of opioid withdrawal episodically and, 3) decrease opioid use due to low barrier accessibility of cannabis.

Discussion

Participants reported myriad benefits of opioid and cannabis co-use for reducing patterns of opioid use. These findings have two major harm reduction implications for PWID: 1) the distribution of cannabis via low threshold peer programming and interventions can facilitate changes in opioid use patterns and 2) access to cannabis co-use, potentially alongside existing Medication for Opioid Use Disorder, in treatment settings may improve efficacy of uptake and treatment outcomes and goals for individual PWID.

Characteristics of Cannabis and Opioid Users Among Older U.S. Veterans and Their Health Outcomes: A Longitudinal Perspective

Medical cannabis use among U.S. Veterans has continued to rise. However, data on cannabis use by older Veterans is generally less available. This study aims to understand the characteristics of older Veterans who enrolled in the Medical Cannabis Patient Program in Illinois and analyze their health outcomes and co-use of cannabis and opioids using longitudinal survey data. Overall, participants reported positive outcomes for pain, sleep, and emotional problems because of cannabis use in two survey periods. Approximately, 62% and 85% respondents reported no change in memory and falls, respectively, with only 3% and 1% reporting a negative outcome for the conditions in both surveys. About 20.4% of those who indicated cannabis use only in the initial survey started to co-use opioids in the follow-up survey, while 44.1% of those who indicated the use of both substances in the initial survey reported no longer using opioids in the follow-up survey. However, these changes were not statistically significant (α = 0.05 ) . The logistic regression showed that both clinical and contextual factors affected co-use. In conclusion, older U.S. Veterans may be using cannabis to alleviate their pain and other chronic conditions. More research is needed to understand the effect of cannabis use on reducing or substituting opioids.

The Association Between Self-Reported Anxiety and Retention in Opioid Agonist Therapy: Findings From a Canadian Pragmatic Trial

BACKGROUND

Prescription-type opioid use disorder (POUD) is often accompanied by comorbid anxiety, yet the impact of anxiety on retention in opioid agonist therapy (OAT) is unclear. Therefore, this study investigated whether baseline anxiety severity affects retention in OAT and whether this effect differs by OAT type (methadone maintenance therapy (MMT) vs. buprenorphine/naloxone (BNX)).

METHODS

This secondary analysis used data from a pan-Canadian randomized trial comparing flexible take-home dosing BNX and standard supervised MMT for 24 weeks. The study included 268 adults with POUD. Baseline anxiety was assessed using the Beck Anxiety Inventory (BAI), with BAI ≥ 16 indicating moderate-to-severe anxiety. The primary outcomes were retention in assigned and any OAT at week 24. In addition, the impact of anxiety severity on retention was examined, and assigned OAT was considered an effect modifier.

RESULTS

Of the participants, 176 (65%) reported moderate-to-severe baseline anxiety. In adjusted analyses, there was no significant difference in retention between those with BAI ≥ 16 and those with BAI < 16 assigned (29% vs. 28%; odds ratio (OR) = 2.03, 95% confidence interval (CI) = 0.94-4.40; P = 0.07) or any OAT (35% vs. 34%; OR = 1.57, 95% CI = 0.77-3.21; P = 0.21). In addition, there was no significant effect modification by OAT type for retention in assigned (P = 0.41) or any OAT (P = 0.71). In adjusted analyses, greater retention in treatment was associated with BNX (vs. MMT), male gender identity (vs. female, transgender, or other), enrolment in the Quebec study site (vs. other sites), and absence of a positive urine drug screen for stimulants at baseline.

CONCLUSIONS

Baseline anxiety severity did not significantly impact retention in OAT for adults with POUD, and there was no significant effect modification by OAT type. However, the overall retention rates were low, highlighting the need to develop new strategies to minimize the risk of attrition from treatment.

CLINICAL TRIAL REGISTRATION

This study was registered in ClinicalTrials.gov (NCT03033732).

Stigma-related barriers to medical cannabis as harm reduction for substance use disorder: Obstacles and opportunities for improvement

Emerging evidence on substituting cannabis for more harmful drugs has led to cannabis becoming a novel harm-reduction strategy for combating the current drug poisoning crisis. However, the authorization of medical cannabis as part of a harm-reduction approach and recovery strategy has significant implementation barriers rooted in longstanding stigma towards cannabis. Through a multi-discipline collaboration of Canadian clinicians and academic researchers, we highlighted stigma barriers and opportunities to address these barriers to elicit improved delivery of medical cannabis as a harm-reduction therapy within existing therapeutic frameworks. Evidence from existing literature and real-world experiences converged on three key themes related to stigma barriers: (1) Lack of medical cannabis education within the healthcare community, (2) lack of consensus and coordination among harm-reduction services and (3) access to medical cannabis. We highlight potential solutions to these issues, including improved healthcare education, better coordination between care teams and suggestions for improving access. Through this discussion, we hope to contribute to reducing the stigma around using medical cannabis as a harm-reduction strategy for individuals with a substance use disorder and consider new perspectives in policy development surrounding recovery services.

"The Box Has Become an Indispensable Part of My Life": A Case Study of Victoria Cannabis Buyers Club and its Consumption Space

Community-based models of cannabis cultivation, distribution, and consumption-such as cannabis clubs-have been documented across Europe, North America, South America, and New Zealand since the 1990s. For the most part, these models have a history of operating outside existing legislation and regulations. Jurisdictions that have legalized cannabis have approached community-based models in opposite ways (eliminate vs. regulate). Canada legalizing cannabis has resulted in more stringent enforcement and concerted efforts to close these models despite documented health and social benefits. This paper presents a case study of the Victoria Cannabis Buyers Club (VCBC) and its consumption space-The Box. We conducted a survey of VCBC members to explore four domains: demographics, cannabis consumption, access to and use of The Box, and the impact of its temporary closure due to COVID-19. From the survey data (n = 104), descriptive statistics were generated and three conceptual avenues were identified. The majority of respondents were 40 years old and older and identified as White (European descent) cisgendered men and women. The majority reported an income of $40,000 or less and a housing status that prevented them from smoking. Close to 75% of our sample consumed cannabis multidaily for therapeutic purposes primarily, but also for a mix of recreation, social, spiritual, and traditional healing purposes. Smoking was the preferred mode of consumption. Respondents accessed The Box daily or weekly. Reasons and benefits for using The Box fell into three categories: public health, harm reduction, and wellness perspectives. Conceptually, we found that The Box acted as a therapeutic space and offered a much-needed consumption space for smokers. We also identified a need to unpack the concept of safety. Overall, the survey reinforces the need for an equity-informed approach to community-based models and cannabis consumption spaces in Canada.

Food insecurity during the COVID-19 pandemic who use drugs in Vancouver, Canada

OBJECTIVE

To examine prevalence and factors associated with food insecurity among people who use drugs (PWUD) during the first year of the COVID-19 pandemic and the overdose crisis.

DESIGN

This cross-sectional study employs multivariable logistic regression to identify factors associated with self-reported food insecurity.

PARTICIPANTS

PWUD who are part of three community-recruited cohorts.

SETTING

Interviews conducted in Vancouver, Canada, via phone between July and November 2020 in adherence to COVID-19 safety procedures.

RESULTS

Among 765 participants, including 433 (56·6 %) men, eligible for this study, 146 (19·1 %; 95 % CI: 16·3 %, 21·9 %) reported food insecurity in the past month. Of the participants reporting food insecurity, 114 (78·1 %) reported that their hunger levels had increased since the beginning of the pandemic. In multivariable analyses, factors independently and positively associated with food insecurity included: difficulty accessing health or social services (adjusted OR (AOR) = 2·59; 95 % CI: 1·60, 4·17); having mobility difficulties (AOR = 1·59; 95 % CI: 1·02, 2·45) and engaging in street-based income generation (e.g. panhandling and informal recycling) (AOR = 2·31; 95 % CI: 1·45, 3·65).

CONCLUSION

Approximately one in five PWUD reported food insecurity during this time. PWUD with mobility issues, who experienced difficulty accessing services and/or those engaged in precarious street-based income generation were more likely to report food insecurity. Food security is paramount to the success of interventions to prevent COVID-19 and drug toxicity deaths. These findings suggest a need for a more unified state response to food insecurity that prioritises and incorporates accessibility and autonomy of the communities they serve.

Women are Taking the Hit: Examining the Unique Consequences of Cannabis Use Across the Female Lifespan

Cannabis use has risen dramatically in recent years due to global decriminalization and a resurgence in the interest of potential therapeutic benefits. While emerging research is shaping our understanding of the benefits and harms of cannabis, there remains a paucity of data specifically focused on how cannabis affects the female population. The female experience of cannabis use is unique, both in the societal context and because of the biological ramifications. This is increasingly important given the rise in cannabis potency, as well as the implications this has for the prevalence of Cannabis Use Disorder (CUD). Therefore, this scoping review aims to discuss the prevalence of cannabis use and CUD in women throughout their lifespan and provide a balanced prospective on the positive and negative consequences of cannabis use. In doing so, this review will highlight the necessity for continued research that goes beyond sex differences.

National Trends in Past-Year Marijuana Use among Veterans in the United States, 2013-2019

Background: The legal landscape surrounding marijuana use in the United States (US) is ever changing. Although substantial research has investigated risk factors of use among different populations, much is to be gleaned among veteran populations, who are at heightened risk for mental and physical health problems, which may be precipitated or relieved by marijuana use. The present study investigated correlates and trends of recreational and medical marijuana use among a large national sample of US Veterans. Methods: Data from the National Survey on Drug Use and Health (2013-2019) comprised of 16,350 veterans 18 years or older were analyzed. We tested for weighted linear and quadratic trends in past-year use. Results: Weighted analyses revealed a significant increase (56%) in overall marijuana use from 2013-2019, with nearly one in 10 veterans (9.79%) reporting past-year marijuana use. Compared to 18 to 25-year-old veterans, veterans who were aged 35-49 years (aPR: 1.44, 95% CI 1.05, 1.97), 50-64 years (aPR: 1.68, 95% CI 1.11, 2.55), and 65 years or older (aPR: 1.90, 95% CI 1.24, 2.90) were more likely to report using medical marijuana in the past year. Conclusions: This increase, in the context of federal VA provider restrictions, has implications for issues of care coordination and safe supply for veterans. Given the rapidly changing and heterogenous landscape of recreational and medical marijuana policy in the US, the present study may inform harm reduction efforts and behavioral interventions.

Lower-Risk Cannabis Use Guidelines (LRCUG) for reducing health harms from non-medical cannabis use: A comprehensive evidence and recommendations update

BACKGROUND

Cannabis use is common, especially among young people, and is associated with risks for various health harms. Some jurisdictions have recently moved to legalization/regulation pursuing public health goals. Evidence-based 'Lower Risk Cannabis Use Guidelines' (LRCUG) and recommendations were previously developed to reduce modifiable risk factors of cannabis-related adverse health outcomes; related evidence has evolved substantially since. We aimed to review new scientific evidence and to develop comprehensively up-to-date LRCUG, including their recommendations, on this evidence basis.

METHODS

Targeted searches for literature (since 2016) on main risk factors for cannabis-related adverse health outcomes modifiable by the user-individual were conducted. Topical areas were informed by previous LRCUG content and expanded upon current evidence. Searches preferentially focused on systematic reviews, supplemented by key individual studies. The review results were evidence-graded, topically organized and narratively summarized; recommendations were developed through an iterative scientific expert consensus development process.

RESULTS

A substantial body of modifiable risk factors for cannabis use-related health harms were identified with varying evidence quality. Twelve substantive recommendation clusters and three precautionary statements were developed. In general, current evidence suggests that individuals can substantially reduce their risk for adverse health outcomes if they delay the onset of cannabis use until after adolescence, avoid the use of high-potency (THC) cannabis products and high-frequency/-intensity of use, and refrain from smoking-routes for administration. While young people are particularly vulnerable to cannabis-related harms, other sub-groups (e.g., pregnant women, drivers, older adults, those with co-morbidities) are advised to exercise particular caution with use-related risks. Legal/regulated cannabis products should be used where possible.

CONCLUSIONS

Cannabis use can result in adverse health outcomes, mostly among sub-groups with higher-risk use. Reducing the risk factors identified can help to reduce health harms from use. The LRCUG offer one targeted intervention component within a comprehensive public health approach for cannabis use. They require effective audience-tailoring and dissemination, regular updating as new evidence become available, and should be evaluated for their impact.

The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems. In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development. The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development. The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases. This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as "C. sativa L." or "medical cannabis"), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.

Prevalence and correlates of non-fatal overdose among people who use drugs: findings from rapid assessments in Massachusetts, 2017-2019

BACKGROUND

People who experience non-fatal overdose (NFOD) are at high risk of subsequent overdose. With unprecedented increases in fentanyl in the US drug supply, many Massachusetts (MA) communities have seen a surge in opioid-related overdoses. The objective of this study was to determine factors associated with lifetime and past year NFOD in at-risk MA communities.

METHODS

We conducted multiple rapid assessments among people who use drugs (PWUD) in eight MA communities using non-probability sampling (purposive, chain referral, respondent-driven) methods. We collected sociodemographic, substance use, overdose history, substance use treatment, and harm reduction services utilization data. We examined the prevalence of NFOD (lifetime and past year) and identified factors associated with NFOD through multivariable logistic regression analyses in a subset of 469 study participants between 2017 and 2019.

RESULTS

The prevalence of lifetime and last year non-fatal opioid overdose was 62.5% and 36.9%, respectively. Many of the study participants reported heroin (64%) and fentanyl (45%) use during the 30 days preceding the survey. Nonprescription buprenorphine and fentanyl use were independently associated with higher odds of lifetime NFOD, while marijuana use was associated with lower odds of lifetime NFOD (p < 0.05). Injection as the route of administration, benzodiazepine, nonprescription buprenorphine, heroin, and fentanyl use were independently associated with higher odds, while methadone use was associated with lower odds of past year NFOD (p < 0.05).

CONCLUSION

We documented a high prevalence of past year and lifetime NFOD among PWUD in MA. Our findings provide indicators that can help inform interventions to prevent overdoses among PWUD, including overdose prevention, medication treatment, and naloxone distribution.

Consensus-based recommendations for titrating cannabinoids and tapering opioids for chronic pain control

AIMS

Opioid misuse and overuse have contributed to a widespread overdose crisis and many patients and physicians are considering medical cannabis to support opioid tapering and chronic pain control. Using a five-step modified Delphi process, we aimed to develop consensus-based recommendations on: 1) when and how to safely initiate and titrate cannabinoids in the presence of opioids, 2) when and how to safely taper opioids in the presence of cannabinoids and 3) how to monitor patients and evaluate outcomes when treating with opioids and cannabinoids.

RESULTS

In patients with chronic pain taking opioids not reaching treatment goals, there was consensus that cannabinoids may be considered for patients experiencing or displaying opioid-related complications, despite psychological or physical interventions. There was consensus observed to initiate with a cannabidiol (CBD)-predominant oral extract in the daytime and consider adding tetrahydrocannabinol (THC). When adding THC, start with 0.5-3 mg, and increase by 1-2 mg once or twice weekly up to 30-40 mg/day. Initiate opioid tapering when the patient reports a minor/major improvement in function, seeks less as-needed medication to control pain and/or the cannabis dose has been optimised. The opioid tapering schedule may be 5%-10% of the morphine equivalent dose (MED) every 1 to 4 weeks. Clinical success could be defined by an improvement in function/quality of life, a ≥30% reduction in pain intensity, a ≥25% reduction in opioid dose, a reduction in opioid dose to <90 mg MED and/or reduction in opioid-related adverse events.

CONCLUSIONS

This five-stage modified Delphi process led to the development of consensus-based recommendations surrounding the safe introduction and titration of cannabinoids in concert with tapering opioids.

"If I knew I could get that every hour instead of alcohol, I would take the cannabis": need and feasibility of cannabis substitution implementation in Canadian managed alcohol programs

Background

While there is robust evidence for strategies to reduce harms of illicit drug use, less attention has been paid to alcohol harm reduction for people experiencing severe alcohol use disorder (AUD), homelessness, and street-based illicit drinking. Managed Alcohol Programs (MAPs) provide safer and regulated sources of alcohol and other supports within a harm reduction framework. To reduce the impacts of heavy long-term alcohol use among MAP participants, cannabis substitution has been identified as a potential therapeutic tool.

Methods

To determine the feasibility of cannabis substitution, we conducted a pre-implementation mixed-methods study utilizing structured surveys and open-ended interviews. Data were collected from MAP organizational leaders (n = 7), program participants (n = 19), staff and managers (n = 17) across 6 MAPs in Canada. We used the Consolidated Framework for Implementation Research (CFIR) to inform and organize our analysis.

Results

Five themes describing feasibility of CSP implementation in MAPs were identified. The first theme describes the characteristics of potential CSP participants. Among MAP participants, 63% (n = 12) were already substituting cannabis for alcohol, most often on a weekly basis (n = 8, 42.1%), for alcohol cravings (n = 15, 78.9%,) and withdrawal (n = 10, 52.6%). Most MAP participants expressed willingness to participate in a CSP (n = 16, 84.2%). The second theme describes the characteristics of a feasible and preferred CSP model according to participants and staff. Participants preferred staff administration of dry, smoked cannabis, followed by edibles and capsules with replacement of some doses of alcohol through a partial substitution model. Themes three and four highlight organizational and contextual factors related to feasibility of implementing CSPs. MAP participants requested peer, social, and counselling supports. Staff requested education resources and enhanced clinical staffing. Critically, program staff and leaders identified that sustainable funding and inexpensive, legal, and reliable sourcing of cannabis are needed to support CSP implementation.

Conclusion

Cannabis substitution was considered feasible by all three groups and in some MAPs residents are already using cannabis. Partial substitution of cannabis for doses of alcohol was preferred. All three groups identified a need for additional supports for implementation including peer support, staff education, and counselling. Sourcing and funding cannabis were identified as primary challenges to successful CSP implementation in MAPs.

Cannabis use is associated with reduced risk of exposure to fentanyl among people on opioid agonist therapy during a community-wide overdose crisis

BACKGROUND

The ongoing opioid overdose crisis is driven largely by exposure to illicitly-manufactured fentanyl. Preliminary observational and experimental research suggests that cannabis could potentially play a role in reducing use of prescription opioids among individuals with chronic pain. However, there is limited data on the effects of cannabis on illicit opioid consumption, particularly fentanyl, especially among individuals on opioid agonist therapy (OAT). We sought to assess the longitudinal association between cannabis use and exposure to fentanyl among people on OAT.

METHODS

Data were drawn from two community-recruited prospective cohorts of people who use drugs in Vancouver, Canada. We used generalized linear mixed-effects modeling, adjusted by relevant confounders, to investigate the relationship between cannabis use and recent fentanyl exposure (both assessed by urine drug testing) among participants on OAT between 2016 and 2018.

RESULTS

Among the 819 participants on OAT who contributed 1989 observations over the study period, fentanyl exposure was common. At the baseline interview, fentanyl was detected in a majority of participants (431, 53 %), with lower prevalence among individuals with urine drug tests positive for tetrahydrocannabinol (47 vs. 56 %, p = 0.028). Over all study interviews, cannabis use was independently associated with reduced likelihood of being recently exposed to fentanyl (Adjusted Prevalence Ratio = 0.91, 95 % Confidence Interval: 0.83 - 0.99).

CONCLUSIONS

Participants on OAT using cannabis had significantly lower risk of being exposed to fentanyl. Our findings reinforce the need for experimental trials to investigate the potential benefits and risks of controlled cannabinoid administration for people on OAT.