Marijuana and Tremor

By: Monique Giroux, MD

The acceptance of medical marijuana is growing and so is the interest in marijuana for tremor and other brain conditions. To date, 20 states have legalized medical marijuana and 13 more have pending legislation.  Marijuana is known for its beneficial effects on pain, chemotherapy-related anorexia and nausea, anxiety and muscle spasms. The role of marijuana in brain disease is just beginning to be explored.

The growing interest in marijuana for tremor is not surprising since traditional medical therapy often falls short of the desired effect. In addition, tremor can change from moment to moment in response to many personal factors such as the tasks or activities a person is performing, emotional unrest, anxiety or stress. In other words, there is a complex interaction between symptom severity and psychological or physical wellbeing and a person’s activity. Marijuana can potentially impact one or more of these factors.

As with any treatment, the following questions must be examined when exploring the role of marijuana as a treatment for tremor:
1.    Are there direct and favorable biochemical or physiologic effects of marijuana on brain function that can improve tremor?
2.    Are observed effects related to other factors such as change in emotional wellbeing or stress?
3.    Are there side effects both immediate and long-term that must be taken in consideration?
4.    What is the role of other associated factors such as cost, change in activity or habits, and stigma that may result from treatment?

Scientific Background
Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant Cannabis sativa. This contains the chemical delta-9-tetrahydrocannabinol (THC). THC is only one of over 70 cannabinoid compounds found in the plant, each with different biological effects. Collectively these compounds are similar to natural occurring chemicals such as anandamide that exist in our bodies and make up the brain’s endocannabinoid system important for brain development and function.

These cannabinoid receptors are located throughout the brain especially in regions that influence cognition, pleasure, motor coordination, time and sensory perceptions. High concentrations of cannabinoid receptors exist in the hippocampus (memory), cerebellum (learning and motor coordination) and basal ganglia (motor control.) Activation of these receptors results in the ‘high’ users experience; as well as change in coordination, problem-solving, mood and altered perceptions such as paranoia or hallucinations.

Potential Medical Use
Marijuana is self-reported to help people manage symptoms of nausea, loss of appetite, muscle spasm, and spasticity, pain and anxiety. There are over 70 identified cannabinoid chemicals in marijuana. These chemical isolates of the marijuana plant have different chemical properties and hence their individual use can be of potential benefit for targeted symptoms. Marinol® is an example of a chemical isolate of marijuana used for a specific medicinal purpose. Marinol® (dronabinol) is synthetic delta-9-tetrahydrocannabinol (delta-9-THC) and an FDA approved medicine for nausea. Sativex® is a mouth spray approved in Europe for multiple sclerosis related muscle spasticity and contains delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD).

Our understanding of the chemical properties of these compounds is in its infancy but laboratory research suggests that some of these compounds have brain-protective effects. Both THC and CBD are powerful antioxidants exerting neuroprotective effects in research models of head injury and neurodegenerative disease. Cannabidiol (CBD) holds promise for medical use since it does not have the psychoactive affects described with the marijuana plant or THC compound. Cannabidiol has anti-inflammatory, antioxidant and immunosuppressive properties measured in the laboratory; properties that may be especially important to brain disease such as MS, head injury, Alzheimer’s disease and Parkinson’s disease.

Tremor is a symptom of many conditions including essential tremor, Parkinson’s disease, MS, head injury, metabolic abnormalities and can be caused by some medications. There is limited research to guide the use of marijuana for tremor and even less understanding of how different types of tremor may or may not respond. An early study of 5 patients with Parkinson’s disease by Frankel and colleagues (1990) showed no tremor benefit after smoking marijuana despite personal accounts of prior beneficial effects. The drug did have an effect on brain chemistry given the drowsiness and euphoria experienced during the study. In 2013, Lotan and colleagues studied 20 people with Parkinson’s disease from Israel that smoked marijuana. (Medical marijuana is legal in Israel). They reported an improvement in sleep, pain, tremor and bradykinesia (motor slowness) 30 minutes after smoking marijuana in clinic.

It is not clear whether the benefits measured in these studies are from a direct effect of marijuana on tremor specific brain chemistry or physiology. Marijuana has a complex neurochemistry with combined psychoactive, behavioral and motor effects which alone or combined can impact tremor. For example, tremor will increase with stress and improve with treatments known to enhance relaxation. Marijuana’s behavioral effects may lead to enhanced relaxation, euphoric mood or mitigate the stress response, and this alone could reduce tremor.

Marijuana ‘Side Effects’
The use of marijuana will likely increase as more states legalize marijuana and societal attitudes about this drug evolve. Like any drug, marijuana use is not without risk. There are potential negative effects of marijuana and its chemical isolates that are noted below:

Behavioral Effects
•    Psychoactive effects of marijuana can have negative short-term and long-term consequences. For example, sedation, apathy and depression can worsen with use and exacerbate any sedating properties of anti-tremor medication.
•    Marijuana can cause psychosis or altered mental states. The elderly, people with cognitive problems, dementia or mental illness may be more susceptible to experiencing these side effects.  The combined risk of marijuana in these populations is unknown.
•    Apathy can lead to lifestyle changes or habits such as lower activity and exercise levels, poorer eating habits and social withdrawal which can impact the brain and general health.
•    Stress certainly worsens tremor and marijuana may indeed have a positive impact on stress physiology. Since there are risks to using marijuana, other alternatives that combat stress such as meditation, guided imagery, exercise and yoga should be considered as treatments with lower risk and perhaps broader general health gains. These anti-stress techniques should not be overlooked as part of a holistic approach to managing tremor.

General Health Effects
•    Heart rate is increased by 20-100 percent for up to 3 hours after smoking marijuana with an increased risk of heart attack one hour after use.
•    Pregnancy. Marijuana can alter the developing endocannabinoid system in the brain of the fetus. Consequences for the child may include problems with attention, memory, and problem solving.
•    Smoking. The long-term impact of smoke inhalation and chemical particulates on lung function is unknown.
•    Stroke. THC causes brain artery constriction and atherosclerosis with may lead to stroke. Whether this is true for all users is unknown.

Other Effects
•    Medical marijuana is legal in some states but is still an unregulated drug with associated risks including potency, contamination, and impurities. Synthetic marijuana is often ‘laced’ with other psychoactive compounds to increase the users ‘high.’
•    Addiction and Long-term use. About 9 percent of users become addicted to marijuana. Younger individuals and daily users have an increased risk. Withdrawal symptoms include irritability, sleeplessness, decreased appetite, anxiety, and drug craving.
•    Long-term marijuana use can impact memory, learning, judgment and increase the risk of mental illness such as psychosis or depression and addiction.
•    Impaired judgment and motor coordination can double the risk of a motor vehicle accident and this increases substantially if combined with alcohol.

As with any drug, there are pros and cons to using marijuana and it is important to review these with your healthcare provider. In particular, the potential addictive, psychoactive and behavioral consequences of marijuana use must be taken into consideration. Nevertheless, specific cannabinoids found in marijuana hold promise as therapeutic agents for neurologic conditions offering yet another strategy for treatment, especially when traditional medications have failed or cause intolerable side effects.

Dr. Monique Giroux is co-founder of the Movement and Neuroperformance Center of Colorado in Englewood, CO and medical director of movement disorders for Swedish Medical Center. She is board certified in Neurology with specialized training in Botulinum toxin (Botox®) for dystonia, pain, and spasticity as well as deep brain stimulation for tremor, dystonia and Parkinson’s disease. She is also medical director of the Northwest Parkinson’s Foundation Wellness Center, and project leader for the National Parkinson’s Foundation Care Center Consortium project.