Emerging Issues in Cannabis and Workers’ Compensation
Setting Priorities for Future Research
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The cannabis sativa plant has a long history of use as an industrial, medical, and recreational product. Cannabis contains hundreds of chemicals, including the main psychoactive compound delta-9-tetrahydrocannabinol (Δ9-THC) and anti-inflammatory constituents such as cannabidiol (CBD). In 1970, cannabis was categorized by the United States federal Controlled Substances Act (CSA) as a Schedule I substance, which the Act defines as a drug or substance that “has a high potential for abuse, has no currently accepted medical use in treatment in the U.S. and for which there is a lack of accepted safety for use of the drug or substance under medical supervision.” As a result, all cannabis products except hemp, which typically contains 0.3 percent or less Δ9-THC, remain illegal under U.S. federal law. But many states allow cannabis consumption for medicinal purposes, and the use of cannabis for treatment of work-related health conditions and coverage under workers’ compensation insurance are emerging occupational health and safety issues. This article summarizes key issues and outlines areas for further research.
CANNABIS HEALTH EFFECTS A 2015 paper published in the Journal of the American Medical Association (JAMA) describes the acute health effects associated with consuming cannabis, which include lightheadedness, drowsiness, nausea, euphoria, disorientation, confusion, and hallucinations. Frequent and heavy cannabis consumption can lead to chronic health effects, including cannabinoid hyperemesis syndrome, which involves repeated bouts of nausea and vomiting, as well as physical and psychological dependence. Withdrawal symptoms arising from cessation of heavy use can include anxiety, irritability, insomnia, tremors, and decreased appetite. (For more information about these and other health effects from cannabis consumption, refer to the resources on pages 30–31 for papers published in the journals Gut, Addiction Science & Clinical Practice, Drug and Alcohol Dependence, and Substance Abuse and Rehabilitation.) A report from the National Institute on Drug Abuse states that the increasing potency of cannabis, combined with the use of cannabis products with high concentrations of Δ9-THC, “raises concerns that the consequences of cannabis use today could be worse than in the past, particularly among those who are new to cannabis use and in younger users, whose brains are still developing.”
In 2013, the fifth edition of the American Psychiatry Association’s Diagnostic and Statistical Manual of Mental Disorders combined cannabis abuse and dependence into a single entity, Cannabis Use Disorder (CUD), which captures the behavioral disorder that can occur with chronic cannabis use. Several recent studies have found an association between CUD and schizophrenia.
MEDICAL CANNABIS BACKGROUND Cannabis has been used as a medicinal for thousands of years. Public attitudes about cannabis consumption for medical purposes began to change in the 1990s, and currently, 37 U.S. states and the District of Columbia have laws that make cannabis available to consumers with qualifying medical conditions. Allowable medical conditions vary by state, but often include cancer, multiple sclerosis, epilepsy, glaucoma, and other conditions that are characterized by chronic pain, such as low back injuries. Some of the conditions for which cannabis is used may be related to workplace injury or illness.
The evidence supporting the medical use of cannabis to treat such qualifying health conditions is mixed. Systematic reviews published in JAMA and by the National Academies of Sciences, Engineering, and Medicine (NAS) indicate initial evidence supporting the use of cannabis to treat end-of-life pain and some chronic pain, rigidity of muscles due to brain/spinal cord injury or multiple sclerosis, and to prevent nausea and vomiting caused by chemotherapy. However, as NAS notes, there have been few controlled clinical trials for cannabis efficacy in treating many of these conditions. In particular, additional research needs to be conducted to evaluate the use of cannabis for chronic pain management.
The PREPARE Act would establish a commission to study a pathway to the federal regulation of cannabis.
MEDICAL CANNABIS WORKERS’ COMPENSATION INSURANCE REIMBURSEMENT Health insurance carriers generally do not reimburse the costs of medical cannabis because it is not a drug approved by the U.S. Food and Drug Administration (FDA). However, workers’ compensation (WC) is a state-regulated insurance system, and some states do support reimbursement for cannabis costs for certain work-related conditions. This follows the precedents of several provincial WC boards in Canada in allowing limited cannabis reimbursement. A main consideration in WC systems, according to a Mathematica report prepared for the U.S. Department of Labor, is that cannabis may offer a possible alternative to opioids for pain management.
In 2021, NIOSH, together with the International Association of Industrial Accident Boards and Commissions (IAIABC), the Workers Compensation Research Institute (WCRI), and the National Council on Compensation Insurance (NCCI), reviewed sources readily available on the internet to examine the WC insurance laws and administrative regulations for the reimbursement of the costs of cannabis for work-related health conditions. This review was published in the American Journal of Industrial Medicine in 2021. More recently, WCRI published an updated inventory of state WC prescription drug laws in the American Journal of Public Health.
Based on these reviews, states that allow medical cannabis access can be categorized into the following four groups according to their WC cannabis reimbursement status:
• expressly allow: Connecticut, Minnesota, New Hampshire, New Jersey, New Mexico, New York • expressly prohibit: Florida, Maine, Massachusetts, North Dakota, Ohio, Washington • not required: Alabama, Arizona, Arkansas, California, Colorado, Delaware, Illinois, Louisiana, Maryland, Michigan, Mississippi, Montana, Nevada, Oregon, Pennsylvania, South Dakota, Utah, Vermont • silent: Alaska, Hawaii, Missouri, Oklahoma, Rhode Island, Virginia, West Virginia, and the District of Columbia
There are several factors involved in obtaining cannabis WC insurance reimbursement to treat a work-related health condition. First, the worker must have a compensable WC claim for a health condition that is determined to be work related. The worker must also be diagnosed with a qualifying medical condition under their state’s medical cannabis access law and registered in the state’s medical cannabis program. The use of medical cannabis then must be established as reasonable and necessary medical care for the worker as part of the WC claim, which is determined on a case-by-case basis by the treating physician. Since cannabis remains a Schedule I substance under the federal CSA, physicians can “recommend” but cannot “prescribe” the use of cannabis to treat a qualifying medical condition, according to FDA. Cannabis must also generally be established as a medical treatment of last resort. For example, in the case of chronic pain, other treatments such as surgery, physical/cognitive therapy, and other FDA-approved prescription pain relief medications must first be tried and shown to be unsuccessful before cannabis can be recommended.
Some states and provinces also restrict the type of occupation that may be eligible to receive WC reimbursement for cannabis. For example, New Brunswick requires a full risk assessment that includes a “documented review of the potential occupational and worksite risks and potential impact on the work environment and co-workers” as well as “a documented evidence-based review of the potential impact on the individual’s ability to perform safety-sensitive tasks in the workplace, including operating a motor vehicle or equipment,” according to a policy adopted by WorkSafeNB in January 2020.
There are additional medical requirements involving cannabis reimbursement related to dosage, the amount supplied, and ongoing physician monitoring. According to The ASAM Principles of Addiction Medicine, retail cannabis products contain varying levels of Δ9-THC, and a 2016 paper in Biological Psychiatry showed that average levels have increased from 4 percent in 1995 to 15 percent in 2018. Although Δ9-THC levels must be included on cannabis product labelling, there is a lack of uniform standards for processing, testing, and labelling cannabis products. Unlike FDA-approved pharmaceuticals, there is uncertainty regarding the effective dose and frequency of administration of cannabis for many health conditions, as explained in a 2020 paper published in the Journal of Clinical Medicine Research. Dosage can also vary depending on whether the product is inhaled as a vapor or consumed as an edible, and the amount taken.
In the six states that allow WC reimbursement for cannabis, the amount of supplied cannabis that will be reimbursed varies. The limit is smallest in New Hampshire, which allows patients to obtain no more than two ounces of cannabis over ten days. In Connecticut, the amount possessed by a qualifying patient should not “exceed an amount of usable marijuana reasonably necessary to ensure uninterrupted availability for a period of one month.” In New Mexico, the limit is three months. New Mexico is the only state to have developed a WC fee schedule for the amount of cannabis reimbursement allowed.
Workers receiving WC reimbursement for cannabis must also receive ongoing physician monitoring to assess treatment of their condition, adverse side effects, pain management effectiveness, and functional status. For example, Minnesota’s WC medical treatment guidelines state that a key treatment concept is “effective care,” which means “the patient is improving subjectively, the patient’s objective clinical findings are improving and/or the patient’s functional status is improving (such as workability).”
USE OF MEDICAL CANNABIS IN THE WORKPLACE There are concerns that neurocognitive and psychomotor impairment due to the acute effects of cannabis consumption can lead to injuries while performing tasks such as operating vehicles and machinery. A recent systematic literature review published in the journal Substance Use & Misuse found mixed evidence for associations between occupational injury and cannabis consumption.
For these reasons, although many U.S. states allow medical cannabis and six allow cannabis WC reimbursement, no state requires employers to accommodate cannabis use at the workplace. However, twenty-four states and the District of Columbia currently provide antidiscrimination protections to a worker who uses medical cannabis outside the workplace. California will enact such legislation in 2024.
A worker can be the subject of disciplinary action if found to be working “under the influence” or “impaired” at work from cannabis use outside the workplace. In some positions covered by federal workplace drug use rules, an individual with a positive urine drug test for cannabis can be disciplined and even terminated even if the individual is not intoxicated or impaired. In Connecticut, whose statute is representative of most state laws, “nothing […] shall restrict an employer’s ability to discipline an employee from being under the influence of intoxicating substances during working hours.” An injured worker’s WC benefits can also be restricted if intoxication is determined to be a proximate cause of a workplace incident, as explained in a report from the Insurance Information Institute.
Determining impairment from cannabis use is not clear-cut. Research published in the Journal of Medical Toxicology and Mayo Clinic Proceedings shows that urine drug testing for Δ9-THC does not correlate with acute impairment since cannabis is stored in body fat and released into the bloodstream over days or weeks after its initial use. Measurement of Δ9-THC and metabolites in serum or plasma above 5 nanograms per milliliter (ng/ml) may represent a better indicator of impairment, but a medical examination focused on identifying impairment is still recommended by the American Association of Occupational Health Nurses and the American College of Occupational and Environmental Medicine.
MOVING FORWARD Cannabis treatment for work-related health conditions that are unresponsive to conventional medical treatments may increase as more workers petition state courts and administrative agencies for cannabis WC reimbursement. De-scheduling of cannabis on the U.S. federal level would likely accelerate the use of cannabis where it is determined to be a reasonable and necessary treatment for difficult-to-manage work-related health conditions.
Recently, U.S. lawmakers reintroduced a bipartisan bill, the Preparing Regulators Effectively for a Post-prohibition Adult-use Regulated Environment Act of 2023, or the PREPARE Act, to establish a Commission on the Federal Regulation of Cannabis to study a prompt and plausible pathway to the federal regulation of cannabis, and for other purposes.
Anticipating future trends in the U.S. and internationally, cannabis use in WC systems is an emerging occupational health and safety issue that deserves research attention. The following research questions would help inform the issue: 1. Are there any demographic or health condition differences between workers who are able to obtain cannabis WC reimbursement compared to workers who cannot obtain cannabis WC reimbursement? 2. Will cannabis-reimbursed workers differ in their rehabilitation outcomes, returning to productive work differently compared to non-reimbursed workers? 3. How will cannabis WC reimbursement impact opioid overdoses and the risk of developing an opioid use disorder? 4. Will WC insurers that offer cannabis reimbursement experience differences in claim severity? 5. Will reimbursed workers have different permanent disability outcomes? 6. How will increased use of cannabis in WC systems impact workplace safety and health and future incidence of work-related injuries and illnesses? 7. What are the most effective physician and insurer practices for treating a work-related health condition with cannabis?
JOHN HOWARD, MD, MPH, JD, LLM, MBA, is the director of NIOSH and the administrator of the World Trade Center Health Program in the U.S. Department of Health and Human Services.
STEVEN WURZELBACHER, PhD, CPE, ARM, is manager of the Center for Workers’ Compensation Studies (CWCS) at NIOSH.
JAMIE OSBORNE, MPH, CHES, is a public health analyst with the NIOSH Office of the Director.
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