Pots and Pains: Medical Marijuana, Legalization, and its Implications for Physical Therapy

Medical marijuana (cannabis) has been gaining a lot of traction throughout the United States, both in societal acceptance but also legislative approval. There are tons of reasons that  may be fueling this attraction but the medicinal taboo of marijuana is most interesting. In the United States, pain, more specifically chronic pain, continues to rise and medical marijuana may prove valuable. Many physical therapists deal with people in chronic pain everyday and it’s thought that cannabis can be a viable alternative to opioid medication and an adjunct to physical therapy. As independent practitioners, there are many questions that we may need to answer. Patient’s will want to know where it’s legal and the surrounding parameters, how medical marijuana works, its benefits, side effects, and any broader implications it may have on medicine and therapy.  These are questions that patients may ask you, if not already have, and my hope is that we’re prepared to answer logically and appropriately.


As recently as March 2018, there are 29 states where medical marijuana is legal and 9 states (including Washington D.C.) where it’s legal for recreational use. In the majority of these states the use of marijuana can be prescribed to individuals with various health conditions, for example HIV/AIDS, glaucoma, Crohn’s disease, multiple sclerosis, seizure disorders, cancer, PTSD, and chronic pain. Every state has slightly different regulations and the legalities of each can be found here. Even though there are many states where it’s legal, cannabis is still illegal federally.legalization map

Under the Controlled Substances Act (CSA) the federal government doesn’t recognize the difference between medical and recreational use of cannabis. The Controlled Substance Act (CSA) also places substances into schedules or classifications that are supposed to be based on the potential for abuse and medicinal value. The schedules are 1 – 5 and schedule 1 drugs are defined as drugs with no acceptable medical use and high potential for abuse. Cannabis is considered a schedule 1 drug along with heroin, ecstasy, and LSD. The real importance this plays clinically is that it’s deemed to have no medical value, therefore making it difficult to perform biomedical research on it. In order for a facility to perform research on schedule 1 drugs they need to gain approval by the DEA and update security protocols. It isn’t easy or cheap to research  medical marijuana and this is incredibly important to realize.

Pain and Opioid Use

 In the United States, according to an NIH survey in 2012, an estimated 25.3 million adults (11.2 percent) experience chronic pain and nearly 40 million adults (17.6 percent) experience severe levels of pain. Currently, 6 out of every 10 people are prescribed an opioid for non-cancer related pain with 2 out of those 6 receiving an average of 3.5 prescriptions. pain in US

These are HUGE numbers that cannot be ignored because in 2016 there were 116 opioid related deaths per day. This is partly why there’s a large interest in medical marijuana and what it can actually do. Since cannabis is a schedule 1 drug the research into the effectiveness as a substitute to opioids is slow but growing.

There is some preliminary research that’s starting to show that medical marijuana may actually help slow down this epidemic. A study from 2017 by Livingston et al. took a look at the correlation of opioid related deaths and recreational cannabis use in Colorado from 2000 to 2015. What they found was that there was about 1 less death per month in that state. Bachhuber et al. in 2014 wanted to determine the association between the presence of state medical cannabis laws and opioid analgesic overdose mortality from 1999-2010. They found that States with medical cannabis laws had a 24.8% lower mean annual opioid overdose mortality rate compared with states without medical cannabis laws.

Now, with all that said, the opioid crisis has no easy answers or fixes because the cause is multifactorial but it appears that medical marijuana may be improving the current situation.

It’s all about the HIGH maaaan… well not really

 The half-baked use of marijuana in the United States may make someone more averse to the option. I would guess that most people have the perception that to use this as a medical option then you probably look like this…


This isn’t necessarily reality, so how is this used for pain without turning into Cheech and Chong? Well, to start we need to know how cannabis works; mind you it’s extremely complex and I am making this much simpler.

Our body naturally has a system that aids in keeping us healthy and is called the Endocannabinoid system. This system is involved in fertility, pregnancy, pre- and postnatal development, appetite, mood, memory, inflammation, and pain sensation.

The endocannabinoid system is made up of neurological receptor sites called Cannabinoid receptor type 1 (CB1) and Cannabinoid receptor type 2 (CB2) that are activated by cannabinoids that we naturally produce (endogenous cannabinoids) or ingest (exogenous cannabinoids). CB1 receptors are mostly in the central nervous system while CB2 receptors are found throughout the body and cells of the immune system. When cannabinoids activate CB1 receptors there is a modulation in neurotransmitter release, decreasing the amount of L-glutamate, GABA, noradrenaline, dopamine, serotonin, and acetylcholine. This will result in decreased pain transmission, spasticity, and tremors (Manzanares 2006). CB2 receptors, when activated, decrease inflammation resulting in decreased inflammatory associated pain as well as neuropathic pain (Manzanares 2006).

The two primary cannabinoids produced by marijuana are tetrahydrocannabinol (THC) and cannabidiol (CBD). THC produces psychoactive effects or the “high” and CBD balances or inhibits the psychoactive properties of THC as well as induces therapeutic effects for medicinal value. CBD has demonstrated the capability to create analgesia, decrease spasticity, decrease inflammation, and has anti-seizure capabilities without giving someone a “high”. When ingested these cannabinoids work by crossing the blood-brain-barrier to directly affect the central nervous system and immune cells that secondarily effect organs mediated by the autonomic nervous system.

Risks and Rewards

Medical marijuana has shown to be beneficial for some pathologies but there are also negative effects. A clinical review of the current research, performed by Dr. Kevin P. Hill, was published in JAMA and has some pretty interesting insights. The review outlines clinical utility and the effects are as follows…

Short-term Negative Effects

  • Impaired short-term memory
  • Impaired judgment
  • Loss of motor coordination and balance
  • Driving while under the influence may double the risk of involvement in a car accident

Long-term Negative Effects

  • Increased risk of anxiety, depression, psychotic illness, as well as worsen the course of these disorders
  • Increased incidence of chronic bronchitis
  • Increased rates of pneumonia and respiratory tract infections
  • Increased risk of myocardial infarction, stroke, and peripheral vascular disease

Long-term regular marijuana use may also be problematic for the developing brain of young individuals. Dr. Hill points out that a recent study demonstrated changes in brain structures such as the nucleus accumbens and the amygdala that are necessary for our brains reward system and emotions respectively.

Short-term Benefits (Ciccone 2016)

  • Feelings of giddiness
  • Increased perception
  • Euphoria
  • Mood changes described as “mellowing out”
  • Decreased pain, both neuropathic and inflammatory
  • Decreased spasticity in patients with multiple sclerosis
  • Appetite stimulant important for people with wasting diseases such as AIDS
  • Reduces intraocular pressure in glaucoma patients
  • Helps control epileptic seizures as well as symptoms of Tourette’s syndrome

According to Dr. Hill’s review, as of March 2015, there were 6 trials examining chronic pain, 6 trials that investigated neuropathic pain, and 12 trials that focused on multiple sclerosis. Many demonstrated positive results, suggesting that marijuana or cannabinoids may be efficacious for these indications. He also reported that the American Academy of Neurology performed a systematic review of medical marijuana as a beneficial therapy for treating spasticity in neurological conditions and centralized pain.

Implications for Physical Therapy

What does medical and recreational marijuana mean for physical therapy? The basic answer is a lot. As I stated earlier, you may already have patient’s interested in this topic and one of the most important roles we can play in someone’s recovery is our ability to educate. We should be equipped to answer any questions someone may have while still staying in our lane. stay in laneWe are not prescriber’s of medication and we should not present ourselves as such. It’s fine if you provide information to a curious patient that asks. What isn’t okay is anything that may guide someone off of their current medication for medical marijuana. If you are in a state where it can be used recreationally, it’s also not okay to say, “Give it a try, what’s the worst that can happen?” Even though some parts of society treat marijuana as more benign, it’s still not your decision to make. Patient’s may have diseases being treated by a physician that can have adverse reactions to marijuana use. This is why it is so important to make sure your patients are receiving adequate information but appropriate prescribing is done by their physician.

Medical marijuana can also play an important role when your patient is in the clinic with you. If you recall some of the acute risks of marijuana use, include loss of coordination and increased risk of cardiovascular events. Since these risks do exist it’s pretty clear that a clinician needs to monitor vitals as well as take care in balance related activities.

Currently, I don’t have a personal opinion on the matter but I am driven towards evidence. As the evidence grows and becomes clear, cannabis for medicinal use appears to be proving valuable. It’s been shown to help slow the pace of opioid use, decrease chronic pain, and provide other benefits for a variety of conditions. As positive as this seems I do believe that caution should be taken. In 1995 the medical community thought pain should be assessed as the 5th vital sign and since then, rates of opioid use have risen to critical levels. Back then there were many people screaming from the rooftops about the dangers of opioid medication but it fell on deaf ears. So far, evidence has demonstrated that medical marijuana is safer than opioid’s but history tells a story and provides insight that we, as people, tend to repeat. If strong evidence is there then let’s get this one right and be responsible caregivers.

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