High-intensity cannabis use is associated with retention in opioid agonist treatment: a longitudinal analysis

Opioid agonist therapy discontinuation in British Columbia: a cross-sectional study of people who access harm reduction services

OBJECTIVES

This study evaluates the prevalence and correlates of opioid agonist therapy (OAT) discontinuation across British Columbia (BC), using a sample of individuals who used substances and accessed harm reduction sites.

DESIGN

This study uses data from the 2019 cross-sectional Harm Reduction Client Survey (HRCS).

SETTING

The 2019 survey was administered from October to December at 22 harm reduction supply distribution sites across the 5 Regional Health Authorities of BC.

PARTICIPANTS

The 2019 HRCS was administered among individuals who used illicit substances in the past 6 months and were aged 19 years and above.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was defined as self-reported discontinuation of OAT in the past 6 months. Measures of association (χ2 and Fisher's exact tests) and logistic regression models were used to assess the strength of association between OAT discontinuation and demographic, socioeconomic, accessibility, drug use and harm reduction correlates.

RESULTS

Of the 194 participants included, 59.8% self-identified as cis man, 37.6% self-identified as Indigenous, 38.1% were aged 30-39 years and 43.8% had discontinued OAT in the past 6 months. Multivariable logistic regression analyses identified that those aged ≥50 years (AOR=0.12, 95% CI (0.03 to 0.45)) and those who took the survey in medium/large urban areas (AOR=0.27, 95% CI (0.07 to 0.98)) were significantly less likely to discontinue OAT, while those who experienced an overdose in the past 6 months were significantly more likely (AOR=3.77, 95% CI (1.57 to 9.03)) to have discontinued OAT in the past 6 months. Substance use, including opioids and stimulants, was similar among those who continued and discontinued OAT. Of the 73 participants who discontinued OAT and provided a reason, one-third reported discontinuing OAT because treatment was not effective, 27.4% could not get to the pharmacy during open hours, 23.3% could not make their clinic appointment and 15.1% reported challenges with transportation/travel.

CONCLUSIONS

OAT discontinuation prevention efforts for individuals using substances in BC need to address disparities in healthcare accessibility, especially in rural areas and among younger individuals. Continued access to harm reduction services can allow for safer consumption of substances for individuals enrolled in OAT programs.

"Like the Wild West": Health care provider perspectives on impacts of recreational cannabis legalization on patients and providers at a tertiary psychiatric hospital in Ontario, Canada

INTRODUCTION

Legalization has increased cannabis availability in Canada. Research shows complex relationships between cannabis use and mental health, and a need for health care providers to engage with patients about cannabis use. Providers have noted gaps in knowledge and research on the medical effects of cannabis as barriers to service delivery. It is unclear how providers and patients in mental health care settings have been impacted by legalization.

METHODS

From June 1 to July 2, 2021, we conducted a qualitative study involving semi-structured interviews with 20 health care providers in a range of roles (e.g., physicians, pharmacists, nurses) within a psychiatric hospital setting. Participants responded to open-ended questions with follow-up probes on various topics related to cannabis legalization. Topics included impacts on patient mental and physical health, clinical impacts, education and training, legal cannabis retail system and the medical cannabis access system.

RESULTS

Thematic analysis identified several themes in the data. Participants reported that legalization has had some positive impacts relating to clinical care and cannabis safety. They also expressed concerns with increased rates of cannabis use, risks to mental health and ongoing challenges engaging with patients about cannabis. Participants made recommendations for medical educators and regulators (e.g., updated curriculums, clinical guidelines), the mental health care sector (e.g., implementation of standardized screening), government (e.g., public health campaigns, safe use guidelines), the medical cannabis access system (e.g., increased regulation, research), and the legal cannabis system (e.g., zoning changes, point-of-sale information).

CONCLUSIONS

This study begins to address the paucity of data on impacts of legalization from mental health service delivery settings. Findings show that although legalization has had some positive impacts, there are ongoing patient concerns and unmet provider needs. More research is needed to understand the experiences of providers delivering care to populations experiencing mental health and/or substance use concerns who use cannabis in the post-legalization era.

Chronic pain among primary fentanyl users: The concept of self-medication

BACKGROUND

Chronic pain is among the leading causes of disability worldwide, of which only a small percentage of patients receive adequate treatment for. Non-prescribed opioid analgesics are commonly sought out in effort to alleviate unrelieved pain. This study assesses the prevalence and correlates of chronic pain among primary fentanyl users.

METHODS

A cross-sectional and structured survey was conducted with 200 adults who reported fentanyl as their drug of choice from a Vancouver acute care hospital. Presence and levels of chronic pain were determined through self-report.

RESULTS

The majority of participants (n = 130, 72.6%) reported having chronic pain in the past 6 months, with the mean level of pain on a typical day to be 7.6 out of a scale of 10 (SD = 1.9). Majority (n = 85, 65.4%) reported using street opioids to self-medicate, while only 9 (6.9%) reported that their chronic pain was unrelated. Regression analysis indicated that increasing age and co-use of cannabis and opioids were independent associated factors of chronic pain. Higher levels of reported pain on a typical day were further associated with age and self-medication.

CONCLUSIONS

The findings of this study demonstrate a significant association between self-medication and chronic pain among primary fentanyl users in British Columbia. For these individuals, inadequate pain relief may drive continued opioid use, which in turn may increase risks of treatment discontinuation and overdose. Appropriate pain management strategies are crucial to avoid opioid misuse and decrease the large societal burden caused by chronic pain.

SIGNIFICANCE

Our work points to the high prevalence of self-reported chronic pain among individuals who primarily use fentanyl. Among those with self-reported fentanyl use and chronic pain, self-medication with street opioids was found to be common and associated with higher reported pain levels on a typical day. This highlights the need for pain management strategies to be integrated into opioid dependence treatment and more research in the overlap of pain and fentanyl use.

Are gaps in rates of retention on buprenorphine for treatment of opioid use disorder closing among veterans across different races and ethnicities? A retrospective cohort study

INTRODUCTION

The U.S. Veterans Health Administration has undertaken several initiatives to improve veterans' access to and retention on buprenorphine because it prevents overdose and reduces drug-related morbidity. We aimed to determine whether improvements in retention duration over time was equitable across veterans of different races and ethnicities.

METHODS

This retrospective cohort study was conducted among veterans who initiated buprenorphine from federal fiscal years (FY) 2006 to 2020 after diagnosis of opioid use disorder. Using an accelerated failure time model, we estimated the association between time to buprenorphine discontinuation and FY of initiation, race and ethnicity, and other control covariates. We followed veterans from buprenorphine initiation until they discontinued or had a censoring event. We then estimated the predicted median days retained on buprenorphine, the average marginal effect of initiating in a later FY, the same measure by race and ethnicity, the incremental effect of the various racial and ethnic identities in contrast to non-Hispanic White, and the total change in the size of the gap over the 15 years of the study between veterans with a minoritized racial or ethnic identity compared to non-Hispanic White veterans.

RESULTS

Most of the 31,797 veterans in the sample were non-Hispanic White (74.5 %), from urban areas (83.5 %), male (92.0 %), and had significant comorbidities, most frequently anxiety disorders (51.0 %) and depression (63.0 %). Overall, 49.8 % of veterans were retained at least 180 days. The average marginal effect of FY was 7.0 days [95%CI:5.3, 8.8] but was significantly smaller among veterans identifying as Black or African American [3.2 days; 95%CI:2.4, 4.1] or Asian [3.6 days; 95%CI:1.6, 5.7] compared to veterans who identify as non-Hispanic White [7.9 days; 95%CI:5.9, 9.9]. Additional measures of change were significant for veterans identifying as Hispanic White or with two or more races.

CONCLUSION

Although buprenorphine retention in OUD treatment improved for all veterans over the 15-year study period, veterans from most minoritized racial and ethnic groups fell further behind as gains in duration on therapy accrued primarily to non-Hispanic White veterans. Targeted interventions addressing specific challenges experienced by veterans with minoritized identities are needed to close gaps in retention on buprenorphine.

"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.

The Role of Medicinal Cannabis as an Emerging Therapy for Opioid Use Disorder

This narrative review explores current insights into the potential use of medicinal cannabis-related products as an emerging therapy for opioid use disorder in the landscape of increasing knowledge about medicinal cannabis-based products, commercialisation and global legalisation. Preclinical studies have provided preliminary insight into the putative neurobiological mechanisms that underpin the potential for medicinal cannabis to be considered a therapeutic in opioid use disorder and addiction. With the progressive legalisation of cannabis in many jurisdictions worldwide, contemporary research has highlighted further evidence that medicinal cannabis may have efficacy in reducing cravings and withdrawal effects, and therefore may be considered as an adjunct or standalone to current medications for opioid use disorder. Despite this potential, the landscape of research in this space draws from a large number of observational studies, with a paucity of rigorous randomised controlled trials to ascertain a true understanding of effect size and safety profile. With current challenges in implementation that arise from political and legal qualms about adopting medicinal cannabis on the background of associated social stigma, significant hurdles remain to be addressed by government, policy-makers, healthcare providers and researchers before medical cannabis can be introduced globally for the treatment of opioid use disorder.

Denial of prescription pain medication among people who use drugs in Vancouver, Canada

BACKGROUND

People who use drugs experience pain at two to three times the rate of the general population and yet continue to face substantial barriers to accessing appropriate and adequate treatment for pain. In light of the overdose crisis and revised opioid prescribing guidelines, we sought to identify factors associated with being denied pain medication and longitudinally investigate denial rates among people who use drugs.

METHODS

We used multivariable generalized estimating equations analyses to investigate factors associated with being denied pain medication among people who use drugs reporting pain in three prospective cohort studies in Vancouver, Canada. Analyses were restricted to study periods in which participants requested a prescription for pain from a healthcare provider. Descriptive statistics detail denial rates and actions taken by participants after being denied.

RESULTS

Among 1168 participants who requested a prescription for pain between December 2012 and March 2020, the median age was 47 years and 63.0% were male. Among 4,179 six-month observation periods, 907 (21.7%) included a report of being denied requested pain medication. In multivariable analyses, age was negatively associated with prescription denial (adjusted odds ratio [AOR] = 0.98, 95% confidence interval [CI]:0.97-0.99), while self-managing pain (AOR = 2.48, 95%CI:2.04-3.00), experiencing a non-fatal overdose (AOR = 1.51, 95%CI:1.22-1.88), engagement in opioid agonist therapy (AOR = 1.32, 95%CI:1.09-1.61), and daily use of heroin or other unregulated opioids (AOR = 1.32, 95%CI:1.05-1.66) were positively associated with being denied. Common actions taken (n = 895) after denial were accessing the unregulated drug supply (53.5%), doing nothing (30.6%), and going to a different doctor/emergency room (6.1%). The period following the introduction of new prescribing guidelines was not associated with a change in denial rates.

CONCLUSIONS

A substantial proportion of people who use drugs continue to be denied prescriptions for pain, with such denial associated with important substance use-related harms, including non-fatal overdose. Guidelines specific to the pharmaceutical management of pain among people who use drugs are needed.

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.

Longitudinal polysubstance use patterns and non-fatal overdose: A repeated measures latent class analysis

BACKGROUND

Polysubstance use (PSU) is common among people who use opioids (PWUO) and has been associated with drug-related harms. We aimed to identify latent longitudinal PSU classes among a cohort of PWUO and characterize non-fatal overdose risks among different sub-classes over time.

METHODS

We used longitudinal data (2005-2018) from three ongoing prospective cohorts of people who use drugs in Vancouver, Canada. The primary outcome of interest was self-reported non-fatal overdose during the past six months. The primary exposure of interest was longitudinal PSU patterns among PWUO, obtained from repeated measures latent class analysis (RMLCA) of weekly substance use-related outcome indicators. Multivariable generalized estimating equations models were built to assess the association between latent PSU class membership and non-fatal overdose, adjusting for potential sociodemographic, behavioural, and structural confounders.

RESULTS

2627 PWUO were included in the analysis, and 1094 (41.6 %) had experienced at least one non-fatal overdose during the study period. RMLCA revealed five distinct latent longitudinal PSU classes, including low/infrequent use (Class 1; 30 %), primarily opioid and methamphetamine use (Class 2; 22 %), primarily cannabis use (Class 3; 15 %), primarily opioid and crack use (Class 4; 29 %), and frequent PSU (Class 5; 4 %). In comparison with Class 1 (low), membership in all latent PSU classes except Class 3 (cannabis) was associated with increased odds of non-fatal overdose: Class 2 (opioids + meth) vs. Class 1 (Adjusted odds ratios [aOR] = 2.20, 95 % confidence intervals [CI]: 1.51-3.22), Class 4 (opioids + crack) vs. Class 1 (aOR = 1.06, 95 % CI: 0.85-1.33), and Class 5 (frequent) vs. Class 1 (aOR = 2.39, 95 % CI: 1.92-2.97).

CONCLUSION

Our findings highlighted the heterogeneous characteristics of PWUO in terms of patterns of PSU and non-fatal overdose risk. The diverse nature of PWUO and the potential additive or multiplicative impact of using several substances on overdoses should be reflected across the substance use treatment continuum and care provision.

Implications of Cannabis Legalization on Substance-Related Benefits and Harms for People Who Use Opioids: A Canadian Perspective

In 2018, Canada enacted the Cannabis Act, becoming only the second country (after Uruguay) to legalize the recreational consumption of cannabis. Although there is ongoing global disagreement on the risk-benefit profile of cannabis with increasing legalization in many parts of the world, the evidence of rising cannabis use prevalence postlegalization has been consistent. In contrast, postlegalization changes in various cannabis-related metrics have been inconsistent in Canada and other parts of the world. Furthermore, the implications of cannabis legalization on substance-related harms and benefits for people who use unregulated drugs, particularly opioids, remain unclear. Finally, although Canada did not legalize cannabis to address the opioid crisis, there is rising scientific and popular interest in the therapeutic potential of cannabis to mitigate opioid-related harms. This perspective highlights the implications of cannabis legalization on substance-related benefits and harms for people who use opioids, the current state of Canadian research, and suggestions for future directions.

Longitudinal latent polysubstance use patterns among a cohort of people who use opioids in Vancouver, Canada

INTRODUCTION

Polysubstance use (PSU) practices are increasing among people who use opioids (PWUO). However, several aspects of longitudinal PSU patterns among PWUO remain understudied. This study aims to identify person-centred longitudinal patterns of PSU among a cohort of PWUO.

METHODS

Using longitudinal data (2005-2018) from three prospective cohort studies including people who use drugs in Vancouver, Canada, we used repeated measures latent class analysis to identify different PSU classes among PWUO. Multivariable generalised estimating equations models weighted by the respective posterior membership probabilities were applied to identify covariates of membership in different PSU classes over time.

RESULTS

Overall, 2627 PWUO (median age at baseline: 36 [quartile 1-3: 25-45]) were included between 2005 and 2018. We found five distinct PSU patterns, including low/infrequent probability of regular substance use (Class 1; 30%), primarily opioid and methamphetamine use (Class 2; 22%), primarily cannabis use (Class 3; 15%), primarily opioid and crack use (Class 4; 29%) and frequent PSU (Class 5; 4%). Membership in Class 2, 4 and 5 was positively associated with several behavioural and socio-structural adversities.

DISCUSSION AND CONCLUSIONS

Findings of this longitudinal study suggest PSU is the norm among PWUO and highlights the heterogeneous characteristics of PWUO. The diversities within the population of PWUO need to be recognised in addiction care and treatment as well as optimising resource allocation in the response to the overdose crisis.

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.

The Impact of Longitudinal Substance Use Patterns on the Risk of Opioid Agonist Therapy Discontinuation: A Repeated Measures Latent Class Analysis

Polysubstance use is prevalent among individuals on opioid agonist treatment (OAT), yet past studies have focused primarily on distinct substances and their association with OAT retention. Data was collected from two prospective cohorts between 2005 and 2020 in Vancouver, Canada. Among 13,596 visits contributed by 1445 participants receiving OAT, we employed repeated measures latent class analysis using seven indicators and identified four longitudinal substance use classes. Using marginal structural Cox modeling, we found that compared to the primarily crack use class, the two opioid and stimulant use classes carried a higher risk of OAT discontinuation, while the primarily cannabis and crack use class had a lower OAT discontinuation risk. Our findings highlight the need for integrated treatment strategies to manage the co-use of opioids and stimulants during receipt of OAT and suggest future research should explore the potential of cannabis as a harm reduction strategy or adjunctive treatment to OAT. Word count: 150/150.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11469-023-01098-8.

Differential effect of cannabis use on opioid agonist treatment outcomes: Exploratory analyses from the OPTIMA study

INTRODUCTION

Conflictual evidence exists regarding the effects of cannabis use on the outcomes of opioid agonist therapy (OAT). In this exploratory analysis, we examined the effect of recent cannabis use on opioid use, craving, and withdrawal symptoms, in individuals participating in a trial comparing flexible buprenorphine/naloxone (BUP/NX) take-home dosing model to witnessed ingestion of methadone.

METHODS

We analyzed data from a multi-centric, pragmatic, 24-week, open label, randomized controlled trial in individuals with prescription-type opioid use disorder (n = 272), randomly assigned to BUP/NX (n = 138) or methadone (n = 134). The study measured last week cannabis and opioid use via timeline-follow back, recorded at baseline and every two weeks during the study. Craving symptoms were measured using the Brief Substance Craving Scale at baseline, and weeks 2, 6, 10, 14, 18 and 22. The study measured opioid withdrawal symptoms via Clinical Opiate Withdrawal Scale at treatment initiation and weeks 2, 4, and 6.

RESULTS

The mean maximum dose taken during the study was 17.3 mg/day (range = 0.5-32 mg/day) for BUP/NX group and 67.7 mg/day (range = 10-170 mg/day) in the methadone group. Repeated measures generalized linear mixed models demonstrated that cannabis use in the last week (mean of 2.3 days) was not significantly associated with last week opioid use (aβ ± standard error (SE) = -0.06 ± 0.04; p = 0.15), craving (aβ ± SE = -0.05 ± 0.08, p = 0.49), or withdrawal symptoms (aβ ± SE = 0.09 ± 0.1, p = 0.36). Bayes factor (BF) for each of the tested models supported the null hypothesis (BF < 0.3).

CONCLUSIONS

The current study did not demonstrate a statistically significant effect of cannabis use on outcomes of interest in the context of a pragmatic randomized-controlled trial. These findings replicated previous results reporting no effect of cannabis use on opioid-related outcomes.

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.

Methadone Dose, Cannabis Use, and Treatment Retention: Findings From a Community-based Sample of People Who Use Unregulated Drugs

OBJECTIVES

Lower daily methadone dose is negatively associated with retention in methadone maintenance treatment (MMT). Cannabis use during MMT is common, with many patients reporting its use for opioid withdrawal mitigation. We sought to test whether the association between lower MMT dose and treatment retention differs by concurrent high-frequency cannabis use in a community sample of people on MMT.

METHODS

We obtained data from participants initiating MMT in 2 community-recruited prospective cohorts of people who use drugs in Vancouver, Canada. We built multivariable Cox frailty models to estimate the relationships between MMT dose (<90 mg/d vs ≥90 mg/d) and time to treatment discontinuation. We included an interaction term to test whether high-frequency (≥daily) cannabis use modified the measured effect of lower treatment dose on treatment retention.

RESULTS

Between December 2005 and December 2018, 829 participants (54.1%) initiated at least 1 MMT episode and were included in the analysis. Lower MMT dose was strongly positively associated with treatment discontinuation regardless of concurrent high-frequency cannabis use (interaction P > 0.05). Structural factors including homelessness and incarceration were significantly and positively associated with treatment discontinuation.

CONCLUSIONS

Although we previously found the magnitude and strength of the relationship between lower MMT dose and high-frequency unregulated opioid use to be tempered during high-frequency cannabis use periods, this effect measure modification does not appear to translate to time retained in treatment. Cannabis-based interventions to promote retention in MMT are unlikely to produce long-term benefit without addressing external factors that place MMT patients at increased risk of treatment discontinuation.

Preoperative Cannabis Use Associated With an Increased Rate of Reoperation and Postoperative Opioid Use Following Anterior Cervical Decompression and Fusion

Objectives The objective of this retrospective cohort study was to evaluate the associations among preoperative cannabis use, postoperative opioid use, and postoperative outcomes following elective anterior cervical decompression and fusion (ACDF). Methods Patients who underwent one- or two-level ACDF were characterized preoperatively as active cannabis users, former users, or nonusers. Patients were also classified based on history of preoperative opioid use as chronic users, acute users, or nonusers. Groups were compared based on outcomes including the rate of emergency department visits six months postoperatively, rate of readmissions one year postoperatively, rate of reoperation two years postoperatively, and daily postoperative opioid use measured in milligram morphine equivalents (MMEs) at 0-6 months and 6-12 months postoperatively.  Results Of the 198 patients included in this study, 13 (6.6%) were active cannabis users, 11 (5.6%) were former users, and 174 (87.8%) were nonusers. The rate of reoperation within two years was 23.1% for active cannabis users, 0% for former users, and 4.0% for nonusers (p=0.0075). The average daily opioid use in MMEs 6-12 months postoperatively was 49.4 for active cannabis users, 4.1 for former users, and 13.3 for nonusers (p=0.0014). For chronic opioid users, acute users, and nonusers, the average daily opioid use in MMEs 6-12 months postoperatively was 39.9, 18.4, and 5.7, respectively (p<.0001). Conclusions History of cannabis use is associated with increased postoperative opioid use and increased rate of reoperation following elective ACDF.

Mood, sleep and pain comorbidity outcomes in cannabis dependent patients: Findings from a nabiximols versus placebo randomised controlled trial

BACKGROUND

Mood, sleep and pain problems are common comorbidities among treatment-seeking cannabis-dependent patients. There is limited evidence suggesting treatment for cannabis dependence is associated with their improvement. This study explored the impact of cannabis dependence treatment on these comorbidities.

METHODS

This is a secondary analysis from a 12-week double-blind placebo-controlled trial testing the efficacy of a cannabis agonist (nabiximols) against placebo in reducing illicit cannabis use in 128 cannabis-dependent participants. Outcome measurements including DASS-21 (Depression, Anxiety, and Stress subscales); Insomnia Severity Index (ISI); and Brief Pain Inventory (BPI), were performed at weeks 0, 4, 8, 12 and 24. Each was analysed as continuous outcomes and as binary cases based on validated clinical cut-offs.

RESULTS

Among those whose DASS and ISI scores were in the moderate to severe range at baseline, after controlling for cannabis use, there was a gradual decrease in severity of symptoms over the course of the trial. BPI decreased significantly until week 12 and then rose again in the post-treatment period during weeks 12-24. Neither pharmacotherapy type (nabiximols vs placebo) nor number of counselling sessions contributed significant explanatory power to any of the models and were excluded from the final analyses for both continuous and categorical outcomes.

CONCLUSIONS

Participants in this trial who qualified as cases at baseline had elevated comorbidity symptoms. There was no evidence that nabiximols treatment is a barrier to achieving reductions in the comorbid symptoms examined. Cannabis dependence treatment reduced illicit cannabis use and improved comorbidity symptoms, even when complete abstinence was not achieved.

"I got a bunch of weed to help me through the withdrawals": Naturalistic cannabis use reported in online opioid and opioid recovery community discussion forums

A growing body of research has reported on the potential opioid-sparing effects of cannabis and cannabinoids, but less is known about specific mechanisms. The present research examines cannabis-related posts in two large online communities on the Reddit platform (“subreddits”) to compare mentions of naturalistic cannabis use by persons self-identifying as actively using opioids versus persons in recovery. We extracted all posts mentioning cannabis-related keywords (e.g., “weed”, “cannabis”, “marijuana”) from December 2015 through August 2019 from an opioid use subreddit and an opioid recovery subreddit. To investigate how cannabis is discussed at-scale, we identified and compared the most frequent phrases in cannabis-related posts in each subreddit using term-frequency-inverse document frequency (TF-IDF) weighting. To contextualize these findings, we also conducted a qualitative content analysis of 200 random posts (100 from each subreddit). Cannabis-related posts were about twice as prevalent in the recovery subreddit (n = 908; 5.4% of 16,791 posts) than in the active opioid use subreddit (n = 4,224; 2.6% of 159,994 posts, p < .001). The most frequent phrases from the recovery subreddit referred to time without using opioids and the possibility of using cannabis as a “treatment.” The most frequent phrases from the opioid subreddit referred to concurrent use of cannabis and opioids. The most common motivations for using cannabis were to manage opioid withdrawal symptoms in the recovery subreddit, often in conjunction with anti-anxiety and GI-distress “comfort meds,” and to enhance the “high” when used in combination with opioids in the opioid subreddit. Despite limitations in generalizability from pseudonymous online posts, this examination of reports of naturalistic cannabis use in relation to opioid use identified withdrawal symptom management as a common motivation. Future research is warranted with more structured assessments that examines the role of cannabis and cannabinoids in addressing both somatic and affective symptoms of opioid withdrawal.

The prevalence and pattern of cannabis use among patients attending a methadone treatment clinic in Nairobi, Kenya

BACKGROUND

Cannabis use during methadone treatment may negatively impact treatment outcomes. The aim of this study was to determine the prevalence and pattern of cannabis use among patients attending a methadone treatment clinic in Nairobi, Kenya.

METHODS

This was a retrospective study of 874 patients on methadone therapy at a methadone maintenance treatment clinic in Nairobi, Kenya from December 2014 to November 2018. Data on sociodemographic characteristics and drug use patterns based on urine drug screens was collected from patient files. Data was analyzed using Statistical Package for the Social Sciences (SPSS) for windows version 23.0.

RESULTS

Point prevalence of cannabis use was 85.8% (95% CI, 83.3 - 88.0) at baseline and 62.7% (95% CI, 59.5 - 65.8) during follow-up. A pattern of polysubstance use was observed where opioids, cannabis and benzodiazepines were the most commonly used drugs. The mean age of the patients was 35.3 (SD 9.0) years with the majority being male, unemployed (76%), (51.4%) had reached primary level of education, and (48.5%) were divorced or separated. University education was associated with reduced risk for cannabis use OR = 0.1 (95% CI, 0.02-0.8, p = 0.031).

CONCLUSION

Cannabis use is prevalent among patients attending a methadone treatment clinic in Kenya, suggesting need for targeted interventions to address the problem of cannabis use during methadone treatment.

Medical Cannabis Certification Is Associated With Decreased Opiate Use in Patients With Chronic Pain: A Retrospective Cohort Study in Delaware

Background

Opioid medications are commonly used to treat chronic pain around the world. While these medications are quite effective at reducing pain, they can create opioid dependence and lead to further drug addiction. Long-term opioid use has significantly contributed to the “opioid epidemic” that is currently ravaging the United States, leading to opioid overdoses and unintentional deaths, particularly in Delaware.

Objective

To determine if medical marijuana certification helps patients in Delaware with chronic pain reduce their opiate use.

Methods

In this study, we examined individuals who were provided with legal; medical cannabis certifications in the state of Delaware between June 2018 and October 2019 and were concurrently being treated with opioid medications for chronic pain at a private pain management practice. Using a posthoc analysis, we conducted a retrospective cohort study on the individuals (n = 81) to determine if there was a decrease in their opioid use following medical cannabis certification. Opioid use was measured in morphine milligram equivalent (MME) through the Delaware prescription monitoring program (PMP) database.

Results

Overall, the average change in prescribed opioid use was found to be -12.3 morphine milligram equivalent (MME) units when including all individuals (p < 0.00001). Among the included individuals with baseline opioid use, medical cannabis certification was associated with a 31.3% average decrease in opioid use (n = 63). When examining subgroups based upon pain location, individuals with neck pain displayed a 41.5% average decrease in MME (n = 27), while individuals with low back pain were observed to have a 29.4% decrease in opioid use (n = 58). Similarly, individuals with knee pain (n = 14) reduced their opioid use by 32.6%.

Conclusion

The results display an association between medical cannabis certification and a decrease in opiate use among the study group individuals. This study suggests that medical cannabis use may help individuals to reduce their opiate requirements along with physician intervention. More research is needed to validate these findings with appropriate controls and verification of cannabis use.

Prevalence and longitudinal correlates of recent exposure to fentanyl among HIV-positive people who use unregulated drugs during a community-wide overdose crisis

The United States and Canada are experiencing an opioid overdose crisis driven largely by exposure to fentanyl (a potent synthetic opioid), with little known about fentanyl exposure among HIV-positive people who use unregulated drugs (PWUD). We sought to estimate the prevalence and correlates of fentanyl exposure among a community-recruited sample derived from a prospective cohort study of HIV-positive PWUD in Vancouver, Canada. Generalized linear mixed-effects analyses were used to identify longitudinal factors associated with a fentanyl-positive urine drug screen test. Between June 2016-November 2017, 456 participants were recruited and contributed 1007 observations. At baseline, 96% of participants were ART-exposed, 72% had an HIV viral load (VL) <50 copies/mL and 21% had a fentanyl-positive test. Longitudinally, fentanyl-positive tests were characterized by: younger participant age (Adjusted Odds Ratio [AOR] = 0.45), recent non-fatal overdose (AOR = 2.30), engagement in opioid agonist therapy (AOR = 1.91), and at least daily heroin injection (AOR = 11.27). CD4+ cell count was negatively associated with fentanyl urine positivity (AOR = 0.92) (all p < 0.05). We identified several risk factors for overdose linked to fentanyl exposure among this sample, although no link with HIV treatment engagement or detectable HIV VL. Innovative strategies are needed to reduce the harmful effects of the contaminated unregulated drug supply experienced by PWUD.

Different drugs come with different motives: Examining motives for substance use among people who engage in polysubstance use undergoing methadone maintenance therapy (MMT)

BACKGROUND

Substance use motives (i.e., reasons for using a substance) are thought to be the most proximal variable leading to substance use. These motives have been described by various typologies, the most well known being the four-factor drinking motives model which separates motives into enhancement, social, coping, and conformity (Cooper, 1994). Although extensively studied in adult community samples, motives for use have less commonly been investigated among populations at a later stage of addiction, where polysubstance use is more common. Moreover, because the motives literature has largely focused on drinking motives, it is not clear whether existing findings can also be applied to other substances (Cooper et al., 2016).

METHODS

Using Zero-inflated beta Bayesian linear mixed modeling, we investigated the stability of seven distinct substance use motives (enhancement, social, expansion, coping with anxiety, coping with depression, coping with withdrawal, and conformity) across six different drug categories (tobacco, alcohol, cannabis, opioids, stimulants, and tranquilisers) to determine the extent to which drug class can influence motive endorsement. One-hundred-and-thirty-eight methadone maintenance therapy (MMT) clients (F = 34.1%; M = 65.9%; age = 40.18 years) completed a novel short-form polysubstance motives questionnaire.

RESULTS

External motives (i.e., conformity and social motives) were the most stable across drug categories, while all internal motives (i.e., enhancement, expansion, and all three coping motives) demonstrated varying levels of inter-drug variability.

CONCLUSIONS

These findings have important implications for prevention and intervention strategies among people who engage in polysubstance use, highlighting the importance of both universal and substance-specific programming.

The effect of person, treatment and prescriber characteristics on retention in opioid agonist treatment: a 15-year retrospective cohort study

BACKGROUND AND AIMS

There is limited evidence on the relationship between retention in opioid agonist treatment for opioid dependence and characteristics of treatment prescribers. This study estimated retention in buprenorphine and methadone treatment and its relationship with person, treatment and prescriber characteristics.

DESIGN

Retrospective longitudinal study.

SETTING

New South Wales, Australia.

PARTICIPANTS

People entering the opioid agonist treatment programme for the first time between August 2001 and December 2015.

MEASUREMENTS

Time in opioid agonist treatment (primary outcome) was modelled using a generalized estimating equation model to estimate associations with person, treatment and prescriber characteristics.

FINDINGS

The impact of medication type on opioid agonist treatment retention reduced over time; the risk of leaving treatment when on buprenorphine compared with methadone was higher among those who entered treatment earlier [e.g. 2001-03: odds ratio (OR) = 1.59, 95% confidence interval (CI) = 1.45-1.75] and lowest among those who entered most recently (2013-15: OR = 1.23, 95% CI = 1.11-1.36). In adjusted analyses, risk of leaving was reduced among people whose prescriber had longer tenure of prescribing (e.g. 3 versus 8 years: OR = 0.94, 95% CI = 0.93-0.95) compared with prescribers with shorter tenure. Aboriginal and Torres Strait Islander people, being of younger age, past-year psychosis disorder and having been convicted of more criminal charges in the year prior to treatment entry were associated with increased risk of leaving treatment.

CONCLUSION

In New South Wales, Australia, retention in buprenorphine treatment for opioid dependence, compared with methadone, has improved over time since its introduction in 2001. Opioid agonist treatment retention is affected not only by characteristics of the person and his or her treatment, but also of the prescriber, with those of longer prescribing tenure associated with increased retention of people in opioid agonist treatment.

Association between Participation in Counseling and Retention in a Buprenorphine-Assisted Treatment Program for People Experiencing Homelessness with Opioid Use Disorder

The opioid epidemic is a public health crisis that disproportionately affects our unsheltered neighbors. Because medication-assisted treatment (MAT) is effective for preventing deaths from drug overdose and retention is associated with better health outcomes, there is a clear need for more research on factors impacting retention in care. This retrospective cohort analysis examines the relationship between attendance in counseling and retention on buprenorphine for three or more months for individuals experiencing homelessness being treated at a Federally Qualified Health Center (FQHC) and Public Health Service Act §330(h) Health Care for the Homeless Program grantee in San Diego County, California. The cohort included 306 adults experiencing homelessness who had at least one prescription for buprenorphine and participated in a MAT program between 2017 and 2019. The sample included 64.4% men, almost exclusively white, and 35% lived in a place not meant for human habitation. Of the sample, 97 patients were retained at 3 months and 209 were not. Results from a logistic regression model showed that counseling appointments were positively associated with retention at three months (OR = 1.57, p < 0.001). Findings from this study inform future MAT program design components for people experiencing homelessness.

Green Hope: Perspectives on Cannabis from People who Use Opioids

While states are implementing policies to legalize cannabis for medical or recreational purposes, it remains a Schedule 1 controlled substance with no medical uses according to US federal law. The perception of cannabis depends on social and cultural norms that impact political institutions involved in implementing policy. Because of negative social constructions, such as the "gateway hypothesis," legalization of cannabis has been slow and contentious. Recent studies suggest that cannabis can help combat the opioid epidemic. This paper fills a gap in our understanding of how cannabis is viewed by people who are actively misusing opioids and not in treatment. Using ethnographic methods to recruit participants living in a state that legalized cannabis and a state where cannabis was illegal, survey and interview data were analyzed informed by a social constructionist lens. Findings from their "insider perspective" suggest that for some people struggling with problematic opioid use, cannabis can be beneficial.

"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 Significantly Reduces the Use of Prescription Opioids and Improves Quality of Life in Authorized Patients: Results of a Large Prospective Study

OBJECTIVES

This article presents findings from a large prospective examination of Canadian medical cannabis patients, with a focus on the impacts of cannabis on prescription opioid use and quality of life over a 6-month period.

METHODS

The Tilray Observational Patient Study took place at 21 medical clinics throughout Canada. This analysis includes 1,145 patients who had at least one postbaseline visit, with follow-up at 1, 3, and 6 months. Instruments included a comprehensive cannabis use inventory, the World Health Organization Quality of Life Short Form (WHOQOL-BREF), and a detailed prescription drug questionnaire.

RESULTS

Participants were 57.6% female, with a median age of 52 years. Baseline opioid use was reported by 28% of participants, dropping to 11% at 6 months. Daily opioid use went from 152 mg morphine milligram equivalent (MME) at baseline to 32.2 mg MME at 6 months, a 78% reduction in mean opioid dosage. Similar reductions were also seen in the other four primary prescription drug classes identified by participants, and statistically significant improvements were reported in all four domains of the WHOQOL-BREF.

CONCLUSIONS

This study provides an individual-level perspective of cannabis substitution for opioids and other prescription drugs, as well as associated improvement in quality of life over 6 months. The high rate of cannabis use for chronic pain and the subsequent reductions in opioid use suggest that cannabis may play a harm reduction role in the opioid overdose crisis, potentially improving the quality of life of patients and overall public health.

Opioid use in medical cannabis authorization adult patients from 2013 to 2018: Alberta, Canada

BACKGROUND

The opioid overdose epidemic in Canada and the United States has become a public health crisis - with exponential increases in opioid-related morbidity and mortality. Recently, there has been an increasing body of evidence focusing on the opioid-sparing effects of medical cannabis use (reduction of opioid use and reliance), and medical cannabis as a potential alternative treatment for chronic pain. The objective of this study is to assess the effect of medical cannabis authorization on opioid use (oral morphine equivalent; OME) between 2013 and 2018 in Alberta, Canada.

METHODS

All adult patients defined as chronic opioid users who were authorized medical cannabis by their health care provider in Alberta, Canada from 2013 to 2018 were propensity score matched to non-authorized chronic opioid using controls. A total of 5373 medical cannabis patients were matched to controls, who were all chronic opioid users. The change in the weekly average OME of opioid drugs for medical cannabis patients relative to controls was measured. Interrupted time series (ITS) analyses was used to assess the trend change in OME during the 26 weeks (6 months) before and 52 weeks (1 year) after the authorization of medical cannabis among adult chronic opioid users.

RESULTS

Average age was 52 years and 54% were female. Patients on low dose opioids (< 50 OME) had an increase in their weekly OME per week (absolute increase of 112.1 OME, 95% CI: 104.1 to 120.3); whereas higher dose users (OME > 100), showed a significant decrease over 6 months (- 435.5, 95% CI: - 596.8 to - 274.2) compared to controls.

CONCLUSIONS

This short-term study found that medical cannabis authorization showed intermediate effects on opioid use, which was dependent on initial opioid use. Greater observations of changes in OME appear to be in those patients who were on a high dosage of opioids (OME > 100); however, continued surveillance of patients utilizing both opioids and medical cannabis is warranted by clinicians to understand the long-term potential benefits and any harms of ongoing use.

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.

Trajectories of Retention in Opioid Agonist Therapy and Overdose Risk During a Community-Wide Overdose Epidemic in a Canadian Setting

INTRODUCTION

Retention in opioid agonist therapy consistently has been linked with improved outcomes among people with opioid use disorder. However, less is known about the links between patterns of engagement in opioid agonist therapy over the long term and overdose risk. This study assesses the association of opioid agonist therapy retention trajectories with nonfatal overdose.

METHODS

Data were drawn from 2 community-recruited prospective cohorts of people who use drugs in Vancouver, Canada. Latent class growth analysis was used to identify trajectories of opioid agonist therapy retention among people with opioid use disorder initiating therapy, and generalized estimating equations assessed the association of these trajectories with nonfatal overdose events after opioid agonist therapy initiation.

RESULTS

Between 2005 and 2018, among 438 opioid agonist therapy initiators, 4 retention trajectories were identified: consistently high (35.6%), increasing (26.0%), consistently low (23.3%), and decreasing (15.1%) opioid agonist therapy engagement. During the study period, there were 371 nonfatal overdose events, with 179 (40.1%) participants reporting ≥1. In adjusted analysis, the consistently low (AOR=1.73, 95% CI=1.10, 2.71) and decreasing (AOR=1.87, 95% CI=1.18, 2.95) retention trajectories were positively associated with increased odds of nonfatal overdose compared with the consistently high opioid agonist therapy retention class.

CONCLUSIONS

Suboptimal trajectories of opioid agonist therapy retention were associated with an increased likelihood of nonfatal overdose. These findings suggest that reducing the barriers to sustained engagement in opioid agonist therapy will be critical to address North America's overdose epidemic.

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.

Frequent Cannabis Use Is Negatively Associated with Frequency of Injection Drug Use Among People Who Inject Drugs in a Canadian Setting

Objectives: High levels of morbidity and mortality associated with injection drug use continue to represent a significant public health challenge in many settings worldwide. Previous studies have shown an association between cannabis use and decreased risk of some drug-related harms. We sought to evaluate the association between high-intensity cannabis use and the frequency of injection drug use among people who inject drugs (PWID). Methods: The data for this analysis were collected from three prospective cohorts of PWID in Vancouver, Canada, between September 2005 and May 2018. Generalized linear mixed-effects models were used to analyze the association between daily cannabis use and the frequency of injecting illegal drugs (i.e., self-reported average number of injections per month). Results: Among the 2,619 active PWID, the frequency of injection drug use was significantly lower among people who use cannabis daily compared with people who use it less than daily (adjusted odds ratio [AOR]=0.84, 95% confidence interval [CI]: 0.73-0.95). Sub-analyses indicated that this effect was restricted to the frequency of illegal opioid injection (AOR=0.78, 95% CI: 0.68-0.90); the association between daily cannabis use and the frequency of illegal stimulant injection was not significant (AOR=1.08, 95% CI 0.93-1.25). Discussion: The findings from these prospective cohorts suggest that people who use cannabis daily were less likely to report daily injection of illegal drugs compared with people who use it less than daily. These results suggest the potential value of conducting experimental research to test whether controlled administration of cannabinoids impacts the frequency of illegal opioid injection among PWID.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

The association of cannabis use late in pregnancy with engagement and retention in perinatal substance use disorder care for opioid use disorder: A cohort comparison

BACKGROUND

Prenatal use of cannabis and opioids are increasing and very concerning. Engagement and retention in comprehensive, perinatal substance use disorder (PSUD) care are associated with better outcomes for mothers and babies. We compared the characteristics and engagement in care among women with opioid use disorder who used cannabis late in pregnancy versus those who didn't.

METHODS

The primary outcome, "overall engagement and retention in PSUD care" included: utilization of substance use treatment prenatally, negative screening/toxicology at delivery (excluding cannabis), and attendance at expected prenatal and postpartum visits. Cannabis use late in pregnancy was objectively assessed at delivery via maternal urine drug screen and/or neonatal meconium/cord toxicology. Between-group comparisons utilized chi square, t-test or Mann-Whitney. Associations were assessed using Spearman Rho and two multivariate, binary logistic regressions for cannabis use and the primary outcome.

RESULTS

18.0% (85/472) consumed cannabis late in pregnancy. Women of color, younger women, and those diagnosed with concurrent cannabis use disorder were more likely to consume cannabis. Engagement and retention in PSUD care was not associated with cannabis use, but rather, with prescribed pharmacotherapy for psychiatric disorders. The use of prescribed buprenorphine+naloxone was associated with cannabis avoidance late in pregnancy.

CONCLUSIONS

Cannabis use late in pregnancy, compared to none, did not impact engagement and retention in our PSUD program. Adjunctive psychotropic medication and/or buprenorphine+naloxone prescription were associated with cannabis avoidance suggesting the use and interactions of pharmacotherapies in an opioid dependent population is complex. A shared decision-making process during PSUD care is warranted.

The cascade of care for opioid use disorder: a retrospective study in British Columbia, Canada

BACKGROUND AND AIMS

The 'cascade of care' framework, measuring attrition at various stages of care engagement, has been proposed to guide the public health response to the opioid overdose public health emergency in British Columbia, Canada. We estimated the cascade of care for opioid use disorder and identified factors associated with care engagement for people with opioid use disorder (PWOUD) provincially.

DESIGN

Retrospective study using a provincial-level linkage of four health administrative databases.

SETTING AND PARTICIPANTS

All PWOUD in BC from 1 January 1996 to 30 November 2017.

MEASUREMENTS

The eight-stage cascade of care included diagnosed PWOUD, ever on opioid agonist treatment (OAT), recently on OAT, currently on OAT and retained on OAT: ≥ 1, ≥ 3, ≥ 12 and ≥ 24 months). Health-care use, homelessness and other demographics were obtained from physician billing records, hospitalizations, and drug dispensation records. Receipt of income assistance was indicated by enrollment in Pharmacare Plan C.

FINDINGS

A total of 55 470 diagnosed PWOUD were alive at end of follow-up. As of 2017, a majority of the population (n = 39 456; 71%) received OAT during follow-up; however, only 33% (n = 18 519) were currently engaged in treatment and 16% (n = 8960) had been retained for at least 1 year. Compared with those never on OAT, those currently engaged in OAT were more likely to be aged under 45 years [adjusted odds ratio (aOR) = 1.75, 95% confidence interval (CI) = 1.64, 1.89], male (aOR = 1.72, 95% CI = 1.64, 1.82), with concurrent substance use disorders (aOR = 2.56, 95% CI = 2.44, 2.70), hepatitis C virus (HCV) (aOR = 1.22, 95% CI = 1.14, 1.33) and either homeless or receiving income-assistance (aOR = 4.35, 95% CI = 4.17, 4.55). Regular contact with the health-care system-either in out-patient or acute care settings-was common among PWOUD not engaged in OAT, regardless of time since diagnosis or treatment discontinuation.

CONCLUSIONS

People with opioid use disorder in British Columbia, Canada show high levels of out-patient care prior to diagnosis. Younger age, male sex, urban residence, lower income level and homelessness appear to be independently associated with increased opioid agonist treatment engagement.

The impact of naturalistic cannabis use on self-reported opioid withdrawal

OBJECTIVES

Four states have legalized medical cannabis for the purpose of treating opioid use disorder. It is unclear whether cannabinoids improve or exacerbate opioid withdrawal. A more thorough examination of cannabis and its impact on specific symptoms of opioid withdrawal is warranted.

METHOD

Two hundred individuals recruited through Amazon Mechanical Turk with past month opioid and cannabis use and experience of opioid withdrawal completed the survey. Participants indicated which opioid withdrawal symptoms improved or worsened with cannabis use and indicated the severity of their opioid withdrawal on days with and without cannabis.

RESULTS

62.5% (n = 125) of 200 participants had used cannabis to treat withdrawal. Participants most frequently indicated that cannabis improved: anxiety, tremors, and trouble sleeping. A minority of participants (6.0%, n = 12) indicated cannabis worsened opioid withdrawal, specifically symptoms of yawning, teary eyes, and runny nose. Across all symptoms, more participants indicated that symptoms improved with cannabis compared to those that indicated symptoms worsened with cannabis. Women reported greater relief from withdrawal with cannabis use than men.

DISCUSSION

These results show that cannabis may improve opioid withdrawal symptoms and that the size of the effect is clinically meaningful. It is important to note that symptoms are exacerbated with cannabis in only a minority of individuals. Prospectively designed studies examining the impact of cannabis and cannabinoids on opioid withdrawal are warranted.

Retention of patients in opioid substitution treatment: A systematic review

Background

Retention in opioid substitution (OST) treatment is associated with substantial reductions in all cause and overdose mortality. This systematic review aims to identify both protective factors supporting retention in OST, and risk factors for treatment dropout.

Methods

A systematic search was performed using MEDLINE, Embase, PsycInfo, CINAHL and Web of Science (January 2001 to October 2019). Randomised controlled trials (RCTs) and observational cohort studies reporting on retention rates and factors associated with retention in OST were included. Factors associated with treatment retention and dropout were explored according to the Maudsley Addiction Profile. A narrative synthesis is provided.

Results

67 studies were included in this review (4 RCTs and 63 observational cohort studies; N = 294,592), all assessing factors associated with retention in OST or treatment dropout. The median retention rate across observational studies was approximately 57% at 12 months, which fell to 38.4% at three years. Studies included were heterogeneous in nature with respect to treatment setting, type of OST, risk factor assessment, ascertainment of outcome and duration of follow-up. While the presence of such methodological heterogeneity makes it difficult to synthesise results, there is limited evidence to support the influence of a number of factors on retention, including age, substance use, OST drug dose, legal issues, and attitudes to OST.

Conclusions

Younger age, substance use particularly cocaine and heroin use, lower doses of methadone, criminal activity/incarceration, and negative attitudes to MMT appear to be associated with reduced retention in OST. A consensus definition of retention is required to allow for comparability across future studies.

The emergence of innovative cannabis distribution projects in the downtown eastside of Vancouver, Canada

The ongoing overdose crisis in the United States and Canada has highlighted the urgent need for innovative interventions to reduce drug-related harms. This, in turn, has led to increased interest in the potential of cannabis as a harm reduction strategy. While Canada has recently legalized cannabis, meaningful barriers to accessing legal cannabis remain for people who use drugs (PWUD) from marginalized communities. In the Downtown Eastside of Vancouver, Canada, innovative, grassroots cannabis distribution programs that dispense cannabis and cannabis products from unregulated sources to PWUD for free have recently emerged. In this study, we draw upon 23 in-depth qualitative interviews and ethnographic fieldwork with PWUD who access these programs. We found that these distribution programs play an important function in bridging access to cannabis for PWUD in a structurally disadvantaged neighborhood and do so by implementing few restrictions on who can access, providing a variety of cannabis products that would otherwise be inaccessible, and distributing cannabis at no cost. In addition, many people reported the program spaces provided an avenue to socialize and connect. Most of our participants reported that legal cannabis was inaccessible both through the legal medical and non-medical systems. Considering Canadian governments have made important regulatory changes in regards to cannabis, understanding emerging patterns and the structural barriers to accessing legal cannabis will be critical to maximizing the potential uses of cannabis as a harm reduction tool and ensuring equitable access to structurally disadvantaged populations. Examining the impact of cannabis use on PWUD and ensuring these groups have access to cannabis is an important component in determining whether cannabis deregulation reduces drug-related harms.

Identifying factors associated with opioid cessation in a biracial sample using machine learning

AIM

Racial disparities in opioid use disorder (OUD) management exist, however, and there is limited research on factors that influence opioid cessation in different population groups.

METHODS

We employed multiple machine learning prediction algorithms least absolute shrinkage and selection operator, random forest, deep neural network, and support vector machine to assess factors associated with ceasing opioid use in a sample of 1,192 African Americans (AAs) and 2,557 individuals of European ancestry (EAs) who met Diagnostic and Statistical Manual of Mental Disorders, 5th Edition criteria for OUD. Values for nearly 4,000 variables reflecting demographics, alcohol and other drug use, general health, non-drug use behaviors, and diagnoses for other psychiatric disorders, were obtained for each participant from the Semi-Structured Assessment for Drug Dependence and Alcoholism, a detailed semi-structured interview.

RESULTS

Support vector machine models performed marginally better on average than other machine learning methods with maximum prediction accuracies of 75.4% in AAs and 79.4% in EAs. Subsequent stepwise regression considered the 83 most highly ranked variables across all methods and models and identified less recent cocaine use (AAs: odds ratio (OR) = 1.82, P = 9.19 × 10-5; EAs: OR = 1.91, P = 3.30 × 10-15), shorter duration of opioid use (AAs: OR = 0.55, P = 5.78 × 10-6; EAs: OR = 0.69, P = 3.01 × 10-7), and older age (AAs: OR = 2.44, P = 1.41 × 10-12; EAs: OR = 2.00, P = 5.74 × 10-9) as the strongest independent predictors of opioid cessation in both AAs and EAs. Attending self-help groups for OUD was also an independent predictor (P < 0.05) in both population groups, while less gambling severity (OR = 0.80, P = 3.32 × 10-2) was specific to AAs and post-traumatic stress disorder recovery (OR = 1.93, P = 7.88 × 10-5), recent antisocial behaviors (OR = 0.64, P = 2.69 × 10-3), and atheism (OR = 1.45, P = 1.34 × 10-2) were specific to EAs. Factors related to drug use comprised about half of the significant independent predictors in both AAs and EAs, with other predictors related to non-drug use behaviors, psychiatric disorders, overall health, and demographics.

CONCLUSIONS

These proof-of-concept findings provide avenues for hypothesis-driven analysis, and will lead to further research on strategies to improve OUD management in EAs and AAs.

Six-month retention and changes in quality of life and substance use from a low-threshold methadone maintenance therapy programme in Durban, South Africa

BACKGROUND

Emerging data points to a potential heroin use epidemic in South Africa. Despite this, access to methadone maintenance therapy and other evidence-based treatment options remains negligible. We aimed to assess retention, changes in substance use and quality of life after 6 months on methadone maintenance therapy provided through a low-threshold service in Durban, South Africa.

METHODS

We enrolled a cohort of 54 people with an opioid use disorder into the study. We reviewed and described baseline socio-demographic characteristics. Baseline and 6-month substance use was assessed using the World Health Organization's Alcohol Smoking and Substance Use Involvement Screening Test (ASSIST) and quality of life, using the SF-12. We compared changes at 6 months on methadone to baseline using the Wilcoxon signed rank test and paired-tests for the ASSIST and SF-12 scores, respectively. McNemar's test was used for comparisons between paired results of categorical variables relating to injecting frequency.

RESULTS

The majority of the participants were young, Black African males, with a history of drug use spanning over 10 years. Retention after 6 months was 81%. After 6 months, the median heroin ASSIST score decreased from 37 to 9 (p < 0.0001) and the cannabis ASSIST score increased from 12.5 to 21 (p = 0.0003). The median mental health composite score of the SF-12 increased from 41.4 to 48.7 (p = 0.0254).

CONCLUSIONS

Interim findings suggest high retention, significant reductions in heroin use and improvements in mental health among participants retained on methadone maintenance therapy for 6 months. Further research into longer term outcomes and the reasons contributing to these changes would strengthen recommendations for the scale-up of methadone maintenance therapy in South Africa.

Is marijuana use associated with decreased use of prescription opioids? Toxicological findings from two US national samples of drivers

Background

State governments in the United States are increasingly viewing marijuana legalization as a policy option for controlling the opioid epidemic under the premise that marijuana is a less harmful substitute for opioids. The purpose of this study is to assess whether marijuana use is associated with decreased odds of prescription opioid use.

Methods

A cross-sectional study design was applied to toxicological testing data from two national samples of drivers: 1) the 2011–2016 Fatality Analysis Reporting System (FARS) and 2) the 2013–2014 National Roadside Survey of Alcohol and Drug Use by Drivers (NRS). Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) estimated from multivariable logistic regression models were used to assess the associations of marijuana use with prescription opioid use and alcohol use.

Results

Among the 47,602 drivers from the FARS, 15.7% tested positive for marijuana and 6.9% positive for prescription opioids. Compared with drivers testing negative for marijuana, those testing positive for marijuana were 28% more likely to test positive for prescription opioids (adjusted OR = 1.28, 95% CI = 1.15–1.42). Among the 7881 drivers from the NRS, 7.9% tested positive for marijuana and 4.5% positive for prescription opioids. Relative to drivers testing negative for marijuana, those testing positive for marijuana were twice as likely to test positive for prescription opioids (adjusted OR = 2.03, 95% CI = 1.29–3.20). In both study samples, marijuana use was associated with significantly increased odds of alcohol positivity.

Conclusions

Drivers who test positive for marijuana are significantly more likely to test positive for prescription opioids. Longitudinal studies with rigorous designs and toxicological testing data are needed to further address the substitution hypothesis between marijuana and prescription opioids.

Trajectories of retention in opioid agonist therapy in a Canadian setting

BACKGROUND

Long-term engagement in opioid agonist therapy (OAT) has been consistently associated with reduced risk for morbidity and mortality in people with opioid use disorder (OUD). However, the dynamic nature of engagement/disengagement in OUD care for over time is poorly captured by traditional metrics. We characterized long-term longitudinal trajectories of engagement in OAT in Vancouver, Canada, between 2005 and 2018.

METHODS

Data were derived from two community-recruited prospective cohorts of people who use drugs. Retention in OAT was defined as self-reported enrolment in OAT for two consecutive follow-up periods (an approximately six-month retention interval). We used latent class growth analysis to identify OAT engagement trajectories during the first five years after OAT initiation and multivariable logistic regression to evaluate predictors of trajectory group membership.

RESULTS

We identified four OAT retention trajectories among 438 OAT initiators: "consistently high" (36%), "consistently low" (23%), "increasing" (23%), and "decreasing" (15%). Employment was a significant cross-cutting predictor of membership of all sub-optimal OAT engagement patterns compared to consistently high trajectories. We also found that initiating OAT after 2014 (when regulatory changes to the provincial OAT program were introduced) was associated with the "consistently low" engagement group relative to others.

CONCLUSIONS

We identified four distinct OAT engagement trajectories in Vancouver, Canada, with employment being a common predictor of sub-optimal care trajectories, suggesting the need to explore alternative OAT models to address employment-related barriers. Care trajectory analysis could help inform tailored interventions to specific populations of people with OUD at specific time points to improve engagement in OAT, and decrease opioid-related morbidity and mortality.

Building a Group-Based Opioid Treatment (GBOT) blueprint: a qualitative study delineating GBOT implementation

BACKGROUND

Group-Based Opioid Treatment (GBOT) has recently emerged as a mechanism for treating patients with opioid use disorder (OUD) in the outpatient setting. However, the more practical "how to" components of successfully delivering GBOT has received little attention in the medical literature, potentially limiting its widespread implementation and utilization. Building on a previous case series, this paper delineates the key components to implementing GBOT by asking: (a) What are the core components to GBOT implementation, and how are they defined? (b) What are the malleable components to GBOT implementation, and what conceptual framework should providers use in determining how to apply these components for effective delivery in their unique clinical environment?

METHODS

To create a blueprint delineating GBOT implementation, we integrated findings from a previously conducted and separately published systematic review of existing GBOT studies, conducted additional literature review, reviewed best practice recommendations and policies related to GBOT and organizational frameworks for implementing health systems change. We triangulated this data with a qualitative thematic analysis from 5 individual interviews and 2 focus groups representing leaders from 5 different GBOT programs across our institution to identify the key components to GBOT implementation, distinguish "core" and "malleable" components, and provide a conceptual framework for considering various options for implementing the malleable components.

RESULTS

We identified 6 core components to GBOT implementation that optimize clinical outcomes, comply with mandatory policies and regulations, ensure patient and staff safety, and promote sustainability in delivery. These included consistent group expectations, team-based approach to care, safe and confidential space, billing compliance, regular monitoring, and regular patient participation. We identified 14 malleable components and developed a novel conceptual framework that providers can apply when deciding how to employ each malleable component that considers empirical, theoretical and practical dimensions.

CONCLUSION

While further research on the effectiveness of GBOT and its individual implementation components is needed, the blueprint outlined here provides an initial framework to help office-based opioid treatment sites implement a successful GBOT approach and hence potentially serve as future study sites to establish efficacy of the model. This blueprint can also be used to continuously monitor how components of GBOT influence treatment outcomes, providing an empirical framework for the ongoing process of refining implementation strategies.

The effect of cannabis laws on opioid use

BACKGROUND

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.

METHODS

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

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.

CONCLUSION

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

Reduced urinary opioid levels from pain management patients associated with marijuana use

Aim: Marijuana use has been postulated to modulate opioid use, dependence and withdrawal. Broad target drug testing results provide a unique perspective to identify any potential interaction between marijuana use and opioid use. Materials & methods: Using a dataset of approximately 800,000 urine drug test results collected from pain management patients of a time from of multiple years, creatinine corrected opioid levels were evaluated to determine if the presence of the primary marijuana marker 11-nor-carboxy-tetrahydrocannabinol (THC-COOH) was associated with statistical differences in excreted opioid concentrations. Results & conclusion: For each of the opioids investigated (codeine, morphine, hydrocodone, hydromorphone, oxycodone, oxymorphone, fentanyl and buprenorphine), marijuana use was associated with statistically significant lower urinary opiate levels than in samples without indicators of marijuana use.

Adverse Consequences of Co-Occurring Opioid Use Disorder and Cannabis Use Disorder Compared to Opioid Use Disorder Only

Background: While there is growing interest in the possibility that cannabis may be a partial substitute for opioids, studies have yet to examine whether individuals with co-occurring opioid and cannabis use disorders (OUD and CUD) have less risk of negative outcomes than those with OUD only. Objective: This study sought to compare the sociodemographic and clinical characteristics of patients diagnosed with co-occurring OUD and CUD to patients with OUD only, CUD only, and patients with any other drug use disorders. We hypothesized that co-occurring OUD and CUD would be associated with lower risk of inpatient admissions and emergency department (ED) visits, lower rates of homelessness, and fewer opioid prescriptions. Methods: Comparisons were based on bivariate analyses, logistic and linear multiple regression models of National Veterans Health Administration (VHA) data from Fiscal Year 2012. Results: Of the 234,181 (94% male) patients diagnosed with drug use disorders, 8.6% were diagnosed with co-occurring OUD and CUD; 33.3% with OUD only; 26.5% with CUD only; and 31.6% with other drug use disorders. Compared to the OUD only group (Mean = 4.8 (SD = 8.84)), the group with co-occurring OUD and CUD was associated with a lower number of opioid prescriptions (Mean = 3.79 (SD = 8.22)) (d = -0.16), but higher likelihood of inpatient psychiatric admission (RR = 1.95) and homelessness (RR = 1.52), and no significant difference in ED visits. Conclusions: These data highlight the need to further investigate whether the complex effects of cannabis use on patients with OUD are counterbalanced by potential benefits of reduced in opioid prescribing.