Understand Medical Cannabis

Many Uses of Medical Cannabis in Canada


Cannabis sativa is a plant that has been used for medical purposes for thousands of years. Cannabis is made up of over 500 compounds and contains more than 100 active compounds called cannabinoids. The remaining compounds are mainly flavonoids, terpenes and fatty acids, all of which have potentially therapeutic benefits.

The two most well-known active cannabinoids are tetrahydrocannabinol (THC) and cannabidiol (CBD). Along with other cannabinoids and compounds found in the cannabis plant, THC and CBD are believed to be the primary compounds responsible for the therapeutic benefits of the plant. The range and extent of therapeutic effects of cannabis  are dependent on the ratio of THC to CBD, as well as their synergy with the remaining compounds of the plant.

Patients who have received authorization from their physician can now access medical cannabis to help manage their symptoms and conditions. Although patients have been using medical cannabis to treat a variety of symptoms and conditions for hundreds of years, the scientific and medical research on the topic is an expanding field.

For more information on the benefits of medical cannabis for specific medical conditions, please visit our Benefits section.



Medical Cannabis for Chronic Pain

Chronic pain affects approximately one in five people and is expected to increase to one in three people over the next two decades.

Patients suffering from chronic pain are often tasked with managing a multitude of physical, psychological and psychosocial factors that accompany their condition. Chronic pain is a commonly occurring symptom of a number of other conditions such as multiple sclerosis, HIV/AIDS, cancer, fibromyalgia, and others. Patients suffering from chronic pain may experience a number of additional frequently occurring symptoms, such as Irritable Bowel Syndrome, headaches, muscle spasms, and disturbances in sleep, among others.

Cannabis has analgesic (pain reducing) and anti-inflammatory properties which may be used in the management of pain symptoms. Research on the analgesic properties of cannabis indicates that cannabis may produce a significant analgesic effect in patients suffering from chronic pain. In addition to reducing pain, clinical trial data also show that cannabis may potentially improve quality and duration of sleep, muscle stiffness and muscle spasticity.

A 2015 study assessing the safety and efficacy of cannabis found that the use of cannabis for the management of chronic, non-cancer, pain had relatively few non-serious Adverse Events (side effects) and did not increase the risk for serious Adverse Events. The study also found that there was a significant improvement in pain, quality of life and physical functioning observed in the group of patients using a standardized dose of cannabis throughout the trial.

Research on the efficacy and safety of cannabis for the treatment of chronic pain is an evolving field. Up-to-date research indicates that cannabis may be an appropriate treatment of patients suffering from chronic pain and associated symptoms.

Breivik H, Collett B, Ventafridda V, Cohen R, Gallacher D (2006) Survey of chronic pain in Europe: prevalence, impact on daily life and treatment. Eur J Pain 10:287–333.
M. E. Lynch, Mark A. Ware (2015) Cannabinoids for the Treatment of Chronic Non-Cancer Pain: An Updated Systematic Review of Randomized Controlled Trials. J Neuroimmune Pharmacol: 1-9.
Lynch ME, Campbell F (2011) Cannabinoids for treatment of chronic non-cancer pain; a systematic review of randomized controlled trials. Br J Clin Pharmacol 72:735–744.
Ware MA, Wang T, Shapiro S, Collet J-P, for the COMPASS study 
team, Boulanger A, Esdaile JM, Gordon A, Lynch M, Moulin DE, O’Connell C, Cannabis for the Management of Pain: Assessment of Safety Study (COMPASS), Journal of Pain (2015), doi: 10.1016/ j.jpain.2015.07.014.

Cannabis and Post Traumatic Stress Disorder

Post Traumatic Stress Disorder (PTSD) can be highly disruptive to the daily lives of patients suffering from its symptoms. These symptoms include flashbacks, nightmares, night-sweats, avoidance of painful stimuli, anxiety, insomnia and others. It is one of the few conditions that can be pinpointed to have begun with a traumatic event or experience.

PTSD is a complex condition which often involves a multi-faceted approach to symptom management. In addition to psychotherapy and traditional pharmacological therapy, many patients report positive outcomes with non-conventional therapies such as medical cannabis.

Research indicates that the endocannabinoid system plays an important role in PTSD symptom management. A study by Greer et al. (2014) showed that 75% of PTSD patients using cannabis reported a reduction in re-experiencing, hyper-arousal and persistent avoidance symptoms.

Similarly, research on animals suggests that cannabis has a great potential to provide anxiety reducing effects. These anxiolytic effects are due to the abundance of CB1 receptors in the part of the brain used to process fear, anxiety and emotional learning. Cannabinoids found in the cannabis plant are able to bind to CB1 sites in the brain, and modulate patients’ responses to anxious memories, thoughts and events.

The endocannabinoid system also plays an important role in the regulation of aversive memories in patients with PTSD. Marsicano and colleagues (2002) conducted an experiment in which CB1 receptors were deleted or significantly reduced in mice, and compared their abilities to acquire fearful memories and to overcome those same memories. Without the CB1 receptors, mice had greater difficulty overcoming fearful memories, but had no problem acquiring them. This suggests that the endocannabinoid system may play a key role in the regulation of emotional responses.

Clinical trials using synthetic THC echo the findings that cannabinoids have the potential to help patients suffering from PTSD work through the fear associated with their memories. A study conducted by Rabinak et al. (2014) was one of the first of its kind to monitor humans’ abilities to overcome fearful memories using a synthetic THC treatment. The study concluded that individuals who received synthetic THC had heightened brain activity in areas associated with overcoming fearful memories.


Greer, George R., Charles S. Grob, Adam L. Halberstadt. (2014) PTSD Symptom Reports of Patients Evaluated for the New Mexico Medical Cannabis Program. Journal of Psychoactive Drugs 46(1): 73.
Jutras-Aswad, D., Prud’Homme, M., & Cata, R. (2015). Cannabidiol as an Intervention for Addictive Behaviors: A Systematic Review of the Evidence. SART Substance Abuse: Research and Treatment, 33. doi:10.4137/sart.s25081
Killeen, T. K., Back, S. E., & Brady, K. T. (2011). The Use of Exposure-Based Treatment Among Individuals With PTSD and Co-occurring Substance Use Disorders: Clinical Considerations. Journal of Dual Diagnosis, 7(4), 194-206. doi:10.1080/15504263.2011.620421
Leeies, M., Pagura, J., Sareen, J., & Bolton, J. M. (2010). The use of alcohol and drugs to self-medicate symptoms of posttraumatic stress disorder. Depression and Anxiety Depress. Anxiety. doi:10.1002/da.20677
Lutz, B. (2007). The Endocannabinoid System and Extinction Learning. Molecular Neurobiology Mol Neurobiol, 36(1), 92-101. doi:10.1007/s12035-007-8004-x
Marsicano, G., Wotjak, C. T., Azad, S. C., Bisogno, T., Rammes, G., Cascio, M. G., . . . Lutz, B. (2002). The endogenous cannabinoid system controls extinction of aversive memories. Nature, 418(6897), 530-534. doi:10.1038/nature00839
Olière, S., Joliette-Riopel, A., Potvin, S., & Jutras-Aswad, D. (2013). Modulation of the Endocannabinoid System: Vulnerability Factor and New Treatment Target for Stimulant Addiction. Frontiers in Psychiatry Front. Psychiatry, 4. doi:10.3389/fpsyt.2013.00109
Qi, W., Gevonden, M., & Shalev, A. (2016). Prevention of Post-Traumatic Stress Disorder After Trauma: Current Evidence and Future Directions. Current Psychiatry Reports Curr Psychiatry Rep, 18(2). doi:10.1007/s11920-015-0655-0
Rabinak, C. A., Angstadt, M., Lyons, M., Mori, S., Milad, M. R., Liberzon, I., & Phan, K. L. (2014). Cannabinoid modulation of prefrontal–limbic activation during fear extinction learning and recall in humans. Neurobiology of Learning and Memory, 113, 125-134. doi:10.1016/j.nlm.2013.09.009
Yarnell, S. (2015). The Use of Medicinal Marijuana for Posttraumatic Stress Disorder. The Primary Care Companion For CNS Disorders Prim. Care Companion CNS Disord. doi:10.4088/pcc.15r01786

Frequently Asked Questions

What is medical cannabis?

Often called marijuana, cannabis refers to the cannabis sativa plant. Cannabis sativa is a species of plant composed of several complex compounds, with the most notable compounds being Tetrahydrocannabinol (THC) and Cannabidiol (CBD).

Is medical cannabis legal?

Yes. It is legal to use cannabis for medical purposes in Canada, provided you:
(1) Have a valid Medical Document (an authorization, similar to a prescription) from your doctor, and
(2) Purchase your medical cannabis from a Licensed Producer.
In 2014, Health Canada introduced the Marihuana for Medical Purposes Regulations (MMPR) which outlines all rules and regulations relating to the use of medical cannabis in Canada.

What is a Licensed Producer?

Under the MMPR patients are required to purchase medical cannabis from a Licensed Producer. Licensed Producers are regulated by Health Canada and follow strict quality control guidelines. Once your doctor authorizes medical cannabis by completing a Medical Document, you are required to select and register with a Licensed Producer, and place an order directly with that producer.

How do I choose a Licensed Producer?

Licensed Producers offer different strains of medical cannabis at different prices. A list of all Licensed Producers is available on Health Canada’s website. If you have a valid Medical Document (prescription) from your doctor, our GrowWise Patient Educators can assist you in choosing a Licensed Producer. Patients typically choose the Licensed Producer based on strain availability and medication cost.

Can I order from more than one Licensed Producer?

The Medical Document (prescription) you receive from your physician can only be sent to one Licensed Producer.

Do I have to smoke my medical cannabis?

There are different ways to consume medical cannabis, including vaporizing, and consuming oils and other derivative products. One mode of consumption may be more helpful for managing a specific symptom, than another. GrowWise can assist you in finding the mode of consumption that would work best for you.

How do I choose the right strain for my condition and symptoms?

The therapeutic effects of cannabis vary according to the content and ratio of THC and CBD compounds of the specific strain type. A GrowWise Patient Educator can assist you in choosing the strain best suited to help you manage your symptoms and condition.