Is it time for a cannabis harm reduction approach? Commentary on ^&

Abstract

Objective:

Recent research suggests potential therapeutic benefits of cannabis-derived products, a lower risk profile than other illicit substances, and significant functional improvement from reduced use. Likewise, low abstinence rates and low motivation to achieve abstinence among those with cannabis use disorder are the norm. As such, the harm reduction model has gained traction among substance use scientists and healthcare professionals as a viable alternative approach. Yet, to date no formal definition of cannabis harm reduction has been proposed.

Method:

We reviewed the literature, including two recent empirical papers published in the Psychology of Addictive Behaviors, Sherman et al. (2022) and Borodovsky et al. (2022), which demonstrate that harm reduction is sufficient to achieve functional improvement. We then propose and define a harm reduction approach for cannabis use research and treatment, and argue why this approach is a timely, necessary discussion.

Results:

We suggest that a cannabis harm reduction approach includes treatment, research, and education initiatives that reduce the public health burden of cannabis use. This approach includes interventions that reduce functional impairment and risk from cannabis, reduced or managed use, and sometimes, but not necessarily, abstinence. Psychoeducation for treatment providers, legislative barriers, and research recommendations are also discussed.

Conclusions:

Research and treatment for cannabis use disorder has historically focused on cannabis abstinence. Treatment trials rarely yield durable abstinence rates, and reduction has recently been tied to functional improvement. We comment on Sherman et al., (2022) and Borodovsky et al., (2022) and propose a shift towards a cannabis harm reduction approach.

Treatment efficacy studies for cannabis use disorder (CUD) have historically focused on achieving abstinence (e.g., Stanger et al., 2013; Witkiewitz et al., 2022). Researchers have defined abstinence in myriad ways, including the proportion of days abstinent, point prevalence abstinence, and continuous days abstinent (Lee et al., 2019). Treatment studies measure these outcomes during and up to 12 months post-treatment (Kesner & Lovinger, 2021). Yet, sustained abstinence is rarely achieved irrespective of how it is defined (e.g., Sayegh et al., 2017; Stephens et al., 2020). Given the discrepancy between abstinence goals and achieved rates, researchers have begun to operationalize reduction outcomes as an alternative. This commentary discusses two recent studies published in the Psychology of Addictive Behaviors, Borodovsky et al. (2022) and Sherman et al. (2022) which sought to address this issue. We discuss these studies within the larger sociopolitical context of legalization and delineate the need for a crucial paradigm shift towards cannabis harm reduction.

The two studies of interest used data from the Achieving Cannabis Cessation Clinical Trial (ACCENT; NCT01675661; Gray, 2018). The two papers took different approaches to investigating cannabis reduction outcomes. Sherman et al. (2022) used cannabis use frequency and quantity-based distributions, evidence from the literature, and clinical expertise to define high-, medium-, and low-risk cannabis use. The results suggested that the magnitude of reduction in quantity- and frequency-based risk levels related to the magnitude of reduction in depression, anxiety, and cannabis-related problems at the end of treatment. The results demonstrated that individuals could achieve clinically meaningful improvements in functioning without abstinence. In the second study, Borodosvky et al. (2022) used latent growth modeling to extract cannabis use trajectories across the treatment trial. Although a two-, three-, four-, and five-class solution fit the data, the magnitude of class-specific use reductions consistently produced similar reductions in cannabis-related problems, confirmed via creatinine-corrected urine cannabinoid concentrations. Given that both studies used the same dataset, it is not surprising that they found magnitude of reduction associated with functional improvement. Yet, rather than a limitation, this converging evidence suggests that harm reduction is an empirically supported, meaningful clinical outcome, which begs the question: is it time for a cannabis harm reduction approach?

Harm reduction is a current, necessary conversation for cannabis researchers because of the rapid changes in legislation in the United States and the lack of consensus regarding cannabis policy. As of January 2023, recreational cannabis is legal in 21 states plus the District of Columbia (D.C.), medical cannabis in 39 states plus D.C., making cannabis illegal in only 11 states. Nearly half of US citizens now live in a state with recreational and medical access, about a third with medical access, and about a quarter with no legal access, as shown in Figure 1. In concordance with these legal changes, the perceived risk of cannabis use has decreased (SAMHSA, 2021) and recent research indicates many potential therapeutic benefits of cannabis-derived products (Bonn-Miller et al., 2014; Matson et al., 2021; Webb & Webb, 2014). These benefits complicate the traditional abstinence-based treatment approach for the subgroup of individuals with CUD who also may benefit from medical use. In this context, a harm reduction model has become a viable alternative among healthcare professionals.

Figure 1. Proportions of States and Population of Cannabis Legality Laws in the United States as of January 2023.

Note. Data collected from the NORML Marijuana State Laws Database

Despite public perception and its potential therapeutic value, cannabis use carries risks. Prevalence of past-month use has more than doubled from 5.9% in 2004 to 13.4% in 2019 (SAMHSA, 2021) and up to 18% of individuals who report past-month use meet the diagnostic criteria for CUD (Centers for Disease Control and Prevention, 2021). Cannabis use is associated with adverse health effects, impaired motor coordination, and risk of psychosis among predisposed individuals (Leung et al., 2020). Outcomes are worse for adolescent-onset heavy use, as evidence suggests deficits in neurocognitive performance, changes in brain structure and function, and lower educational attainment in this population (Levine et al., 2017). From a harm reduction approach, prevention and early-intervention efforts can target early-onset use, while among individuals who develop CUD, treatment providers can work to titrate their dose in a collaborative, goal-oriented manner.

Scientific and public support for cannabis harm reduction face critical challenges ahead. The most notable are legislative challenges as cannabis remains federally illegal and classified as a Schedule I drug under the Controlled Substances Act (United States Drug Enforcement Agency, 2022). With this classification, the United States government deems cannabis to have no known medical value and high abuse liability. The Schedule I classification has significant implications from a harm reduction perspective. First, we recommend that individuals who live in states without cannabis access laws consider abstinence to reduce the harm that may come from legal consequences. For these individuals, a non-abstinent harm reduction approach could have long-term legal or occupational implications such as job loss, difficulty obtaining new employment, or incarceration, which disproportionately affect Black, Hispanic, and Indigenous individuals (Burns et al., 2013; Sheehan et al., 2021; Willits et al., 2022). Second, scientists are restricted in the clearance to obtain and study cannabis. For over 50 years, the University of Mississippi was the only source for DEA-approved research cannabis and the cannabis produced did not reflect the high-THC chemotypes being consumed by the public. In 2022, two additional companies were granted DEA licensure to produce research cannabis, and chemotypes have become more comparable to what is sold in licensed state dispensaries (Zarrabi et al., 2020). Even so, researchers in states with cannabis access laws cannot purchase and investigate products sold legally in their state, limiting their ability to conduct timely and ecologically valid research. These legislative challenges restrict scientific progress critical to informing a harm reduction approach.

To mitigate these challenges, we define cannabis harm reduction as: combined research, treatment, and education initiatives that reduce the public health and individual burden of cannabis use. Towards this end we recommend the following. First, we recommend more research on cannabis reduction. Some studies demonstrate the psychosocial and functional benefits of reducing use, yet this line of research lacks robust evidence. Developing a standard cannabis unit (akin to a standard alcoholic drink) and a reliable measure of intoxication are central to this endeavor and can help determine appropriate dosing, establish standardized reduction outcomes for clinical trials, and correlate reduction outcomes with functional improvement. The National Institute on Drug Abuse (NIDA) recently established 5mg of THC as the standard unit for research. While this unit will facilitate a better understanding of the pharmacokinetics and pharmacodynamics of cannabis, it is not a recommendation for consumption or distribution and does not address the issue of assessing intoxication (e.g., roadside testing). We also advocate for randomized controlled trials of cannabis-derived products for health conditions, such as Crohn’s disease or chronic neuropathic pain to build robust evidence for precision medicine and to inform policy.

Second, safe and efficacious harm reduction approaches for CUD are needed. This includes interventions that reduce functional impairment and risk from cannabis (e.g., psychoeducation about the delayed onset effects of cannabis edibles), reduced or managed use (e.g., specific dosing recommendations from a treatment provider), and sometimes, but not necessarily, abstinence. Reduction goals are generally preferred and more realistic than abstinence-only goals, as even well-supported treatments fail to achieve enduring abstinence (Connor et al., 2021). Sherman et al. (2022), Borodovsky et al. (2022), and others (Hser et al., 2017) present evidence that cannabis reduction without abstinence can improve functional outcomes, which may allow flexibility for safe medical and moderate recreational use. Yet, certain health conditions may have better outcomes with abstinence due to contraindications such as early-onset psychosis or binge eating disorder. Knowing when to recommend reduction versus abstinence is part of a harm reduction model and remains an area for further study.

Third, we must integrate harm reduction into medical education. The current prevailing attitude in the medical field is abstinence-focused, which may not converge with the shift in public perception, the growing evidence base that reduction is a viable alternative for many, and the significant therapeutic potential of cannabis. Physicians must be equipped with current scientific knowledge to speak to patients about the potential risks and benefits of cannabis. Achieving these recommendations may improve functioning for all people who use cannabis by providing a flexible and inclusive approach.

Given the current trends in the United States, prevalence rates of cannabis use and CUD are likely to increase. Integrating a harm reduction approach into legislation and medicine can simultaneously alleviate the risks of cannabis use while advancing the science and application of cannabis-derived therapeutics. As licensed professionals, we are responsible for providing ethical and informed treatment recommendations. Cannabis harm reduction is forward-thinking and reflects a contemporary and scientifically grounded attitude that may be essential to managing the cultural shift in cannabis policy over the next several decades.

Public Health Significance:

Cannabis harm reduction is a critical approach to reducing the public health burden of cannabis use and cannabis use disorder, as traditional abstinence-only models may be insufficient. Cannabis harm reduction includes education, research, and treatment initiatives which seek to minimize risk associated with cannabis use while advancing the science and therapeutic potential of cannabis and cannabis-derived products.