For Hoot Gibson of Aurora, Colorado, using medical marijuana came at the end of a long journey.

Gibson, 44, lives with multiple sclerosis and degenerative disk disease. He experiences pain, tremors, and seizures, among other symptoms.

Over the years, he tried a whole slew of pharmaceutical remedies, including opiate painkillers, anticonvulsants, muscle relaxants, and antidepressants.

“These drugs created addictions, lethargy, loss of interest in daily life and activities while providing no positive results for the symptoms they were supposed to be helping,” Gibson told Healthline.

Finally, disabled, unable to work, and out of other options, Gibson moved to Colorado and began using cannabis products to manage his symptoms.

“I am a ‘medical refugee,’” he said. “I had to move 2,000 miles to be able to have access to medicine that could help me where countless pharmaceuticals had failed.”

While Colorado has offered Gibson a safe haven, it didn’t provide Brandon Coats with the legal protection he said he needs.

Left quadriplegic after a car accident, Coats began using medical cannabis to control leg spasms. He obtained his prescription for the drug in accordance with state law and only used it when he wasn’t at work.

However, when his employer, Dish Network, learned that Coats tested positive on a random drug test, he was promptly fired.

Coats’ defense?

Colorado’s lawful activities statute, which states that employees cannot be terminated for “engaging in any lawful activity off the premises of the employer during nonworking hours.”

Five years of litigation later, the case appeared before the Colorado Supreme Court last month. The justices ruled, in a 6-0 decision, that Coats’ termination was legal.

“Nothing in the language of the statute limits the term ‘lawful’ to state law,” wrote the court. “Instead, the term is used in its general, unrestricted sense, indicating that a ‘lawful’ activity is that which complies with applicable ‘law,’ including state and federal law. We therefore decline Coats's invitation to engraft a state law limitation onto the statutory language.”

“I was disappointed, I was devastated,” said Michael D. Evans, attorney for Coats, in an interview with Healthline. “So was Mr. Coats. We’ve been working on this case five years; we’ve spent thousands of hours working on it. We thought if there was ever a case to win, this would be [it]. This was the best-case scenario and if Brandon couldn’t win this kind of a case, then who else would?”

A Legal Gray Area

The Colorado case brings up concerns for medical cannabis users in other states as well. Even if they’re complying with their own state’s laws and regulations, are they still at risk of losing their jobs?

A 34-year-old San Francisco resident whom we will refer to as “Bob” uses medical cannabis to treat bipolar disorder. He has been following the Colorado case closely.

“It makes me worry about whether I can just get fired, despite the fact [of] whether [or not] I can do my job … I can be fired for trying to make my life better,” he told Healthline.

Every U.S. state except Montana has at-will employment practices, meaning that employers are free to terminate an employee and employees are free to leave their job at any time and for no reason.

However, a number of restrictions apply. For example, you can’t fire someone on the basis of their having a disability or for being a certain race or religion.

But while the American Disabilities Act protects disabled employees from being fired for lawfully using medication to treat their disability, it specifically excludes state-authorized medical cannabis. If other states follow Colorado’s example, then any employee in Bob’s position could be fired.

A few other legal restrictions on the federal level exist already.

For example, the Occupational Safety and Health Act (OSHA) requires employers to provide a safe working environment for their employees. If an employee in a safety-related position is under the influence at work, they could present a danger to their co-workers.

There are also tighter restrictions when taxpayer dollars get involved. The Drug Free Workplace Act of 1988 mandates that employers who wish to be federal contractors or receive federal funding supply drug-free workplace policies.

Outside of those concerns, employers looking to terminate an employee for using medical cannabis might face a number of obstacles.

“One of the key problems for employers if they take adverse action against employees who use medical marijuana which they are authorized to use, is that they’re inviting potential claims,” warned Jonathan R. Sigel, partner in the Labor, Employment and Employee Benefits Group at Massachusetts-based Mirick O’Connell. “Even though they may not be viable claims at this point, they can still cost employers money to defend, since employees and their attorneys will likely find other ways to ‘skin the cat’ — for example, a claim for disability discrimination regarding the underlying medical condition.”

Sigel adds a note of caution: “Be aware that, at this point, the use of medical marijuana is still illegal under federal law, even if it’s legal under certain states’ laws. Therefore, generally, employees should not feel that they are entitled to special accommodations at work just because they’re legally authorized to use medical marijuana.”

Bob doesn’t want his employers to know about his cannabis use, so as long as it remains illegal on a federal level, he’s going to keep it that way.

But change may not be too far in the future.

“Like anything else, the more things get discussed and debated and exposed to media, the more educated and comfortable people can become,” said Evans. “I think that the United States Supreme Court ruling on gay marriage is a good example of that. Ten years ago, that decision never would have happened. I think it’s a matter of time.”

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But Where to Draw the Line?

If cannabis does eventually become legalized for medical use, then it raises a whole new round of questions.

How can states strike a balance between protecting the right of employees to access necessary medications, and the rights of employers to have unimpaired workers?

Evans points to other, currently legal mind-altering medications that employees might take at work.

“Look, how many [chief financial officers] or controllers or accountants have some type of elective surgery, like a bariatric surgery, and then go to work taking Percocet or oxycodone because of the pain?” he said. “All of us have probably had a surgery where we’ve taken one of those drugs because there’s pain right afterward. But we go to work, we do our job, we know that it kind of messes with us, but we go anyway and we’re not fired. In Brandon’s case, he wasn’t even using marijuana at work.”

It comes down to the definition of reasonable accommodations and undue hardship, says Chicago-based employment lawyer Eugene K. Hollander.

“Under the Americans with Disabilities Act, if an employee has a disability, he or she can request that the employer make a reasonable accommodation so that the employee can perform [his or] her job,” he told Healthline. “Generally, if an employee makes such a request, the employer must enter into a meaningful dialogue to see if it can reasonably accommodate the request. The employer does not have to grant the request if the accommodation would pose an undue hardship upon it. Thus, if the employer claims that an employee’s use of medical marijuana would impair his [or her] ability to perform [their] job, [the company] may not be liable if it declines to accommodate.”

Measuring Impairment

There lies the real question: How do we tell if an employee’s cannabis use at home is causing impairment at work?

To start with, “cannabis” refers to a whole plant, which contains hundreds of different compounds called cannabinoids. The most famous such cannabinoid is tetrahydrocannabinol (THC). In the body, THC metabolizes into 11-OH-THC, the psychoactive compound that produces cannabis’ characteristic “high.”

But other cannabinoids, such as cannabidiol (CBD), don’t have psychoactive properties at any point during their metabolism, even though they can still provide symptom relief for many patients.

And the picture gets even more complicated after taking into account that CBD, when combined with THC, amplifies THC’s therapeutic effects while reducing its psychoactive ones. A drug test that simply looked for the presence of any cannabinoids (THC, CBD, or others) could provide an inaccurate assessment of whether the employee had experienced any actual impairment.

“The persistence and intensity of the effects will vary widely depending on potency of the marijuana, history of past/recent use, form of administration, and many other individual factors,” explained Ruben Baler, Ph.D., health scientist at the National Institute on Drug Abuse (NIDA), in an interview with Healthline. “Marijuana produces behavioral and physiological effects. The behavioral effects include feelings of euphoria, relaxation, altered time perception, lack of concentration, and impaired learning. Memory and mood changes such as panic and paranoid reactions have also been reported.”

He added that detectable THC levels usually drop a day or so after use, but in some people — especially habitual or heavy users — they can remain measurable for up to a month. This means that if someone uses cannabis heavily at home, the drug may still be in their body the following day at work.

Which isn’t necessarily a problem, points out Nancy Whiteman, co-founder and co-owner of Wana Brands. Her company manufactures a range of cannabis products. These include an extended-release formulation that provides a slow release of cannabinoids over 12 hours, preventing cannabinoid levels from spiking or crashing. Different products come in different CBD:THC ratios, some as high as 10:1.

Presumably, using the primarily CBD mixture could result in no mind-altering effects at all.

“Whether an employee is using cannabis during the workweek or on their time off, the issue for me is the same,” she told Healthline. “Are they getting the job done? Is their performance where it needs to be? If it isn’t, is there any indication that their lack of performance is related to cannabis? If the cannabis is causing performance problems, the employer certainly has the right and the need to address that. If it is not, I say be grateful that your employee has found a medicine that is helping their condition.”

So is there any way to compare the actual effects of medical cannabis on performance with the effects of other mind-altering drugs that employees might take at work, such as opiate painkillers or tranquilizers? Ruben doesn’t think so.

“This is impossible to answer because it will vary tremendously among different people,” he said.

Anthony Campbell, R.Ph., D.O., clinical specialty consultant with the Substance Abuse and Mental Health Services Administration (SAMHSA), was willing to hazard a guess.

“The impairments associated with marijuana may mimic the impairments of any other substance known for abuse simply because of commonly shared pathways,” he told Healthline.

As for the nature of those impairments?

“Some studies suggest impairments in memory and attention after lengthy, heavy marijuana use persist and worsen with increasing years of regular use or with initiation during adolescence; other evidence suggests long-term cognitive deficits could be reversible or remain subtle and not disabling if chronic users discontinue their marijuana use,” Campbell said.

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More Use May Mean Less Impairment

One study does shed some light on the issue of impairment for habitual medical cannabis users. The researchers found that while cannabis caused substantial impairments for occasional cannabis users, heavy cannabis users showed far fewer impairments.

“The more frequently someone uses cannabis, the less impaired they are after consuming because they adjust and learn how to function with it in their system,” explained Amanda Reiman, manager of marijuana law and policy for the Drug Policy Alliance, in an interview with Healthline.

Bob of San Francisco says this has been his experience.

“I don’t see it as something that impairs my ability to do much of anything,” he said. “I can’t speak for everyone’s experience, but I think after some level of experience with marijuana use, you can generally do most things that you would normally do. I think that there’s this idea that it makes people very much nonresponsive or unable to do something that they might normally be able to do, and I find that very untrue. In some ways, I find that it allows me to accomplish things I might not otherwise be able to do.”

And Impairment Isn’t the Point

And if the drug is causing impairment, then it’s probably not the right drug for the patient.

“Any approach to managing a patient using any [therapy] is to use the therapy to the extent that it achieves the necessary therapeutic objectives but also preserves functional ability, or ideally, improves functional outcomes,” explained Mark Ware, associate professor in family medicine and anesthesia at McGill University and director of Clinical Research at the Alan Edwards Pain Management Unit at the McGill University Health Center, in an interview with Healthline. “For somebody using any drug, cannabis being one of many options, the key issue is to determine that the symptom is being well-managed with the drug, but that it is not being managed at the expense of functional outcomes.”

Ware doesn’t see cannabis as any different from other mind-altering medications in his work treating chronic pain.

“Probably, the most important thing for us to try to do is to treat cannabis and cannabinoids like any other medication,” he said. “These are not questions that are unique with cannabis. They come up with the use of opioids and other strong centrally-acting medications, such as anticonvulsants [or] antidepressants. Risks of impairment related to driving, operating machinery, short-term memory effects, concentration, cognitive function, and so on are all concerns of a wide range of other medicines. One would hope that these considerations are applied equally to cannabis as they are to other therapies.”

A common theme among many of the experts is that it’s not just the employee’s level of impairment to worry about. It’s also the demands of the job at hand.

Losing 50 milliseconds of reaction time might not mean a lot to an administrator, but it could mean the difference between life and death for a pilot, heavy equipment operator, or other high-risk professionals.

Paula Brantner, executive director of Workplace Fairness, proposes a compromise.

“If habitual users could transition to jobs which have no public safety implications, either temporarily while they are engaged in medical cannabis use, or permanently in states where cannabis use has been legalized or decriminalized and the employee has no intention of quitting, then we have a win-win situation conducive to transforming both drug policy and workplace policy,” she suggested.

Brantner thinks blanket drug testing is cumbersome and ineffective compared to individual performance evaluation.

“Company-wide drug testing programs are very expensive and are over-inclusive and under-inclusive at the same time: between false positives and detecting one-time use, they ensnare employees who do not have a problem or present workplace impairment, and detect legitimate medical use, but may not detect those with substance abuse problems who go to great lengths to evade testing,” she said.

She added an employee in the acute stages of untreated depression or who has recently experienced a loss such as death of a loved one may be more impaired than someone who is a habitual cannabis user.

These comparisons — like the comparison of taking painkillers after surgery — look more at short-term impairments than long-term, which would be the case for many medical cannabis users. The accommodation required for long-term cannabis use could require a different approach.

Still, research into medical cannabis is continuing forward, and with it, legislative change.

Brantner concluded, “Many states are rejecting the historical prohibitions and passing marijuana laws consistent with scientific research and social reality. We can shap[e] workplace policies rooted in actual experience and which respect employees’ time off-duty and decisions they and their doctors make about appropriate medical care.”

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