Cannabis and Post-Traumatic Stress Disorder

July 2, 2019

Cannabis and Post-Traumatic Stress Disorder

Dr. Matthew Green, Ph.D.

Approximately 1 in 10 Canadians will suffer from post-traumatic stress disorder (PTSD) in their lifetime, and the prevalence is approximately two-fold greater among Canadian Veterans 1,2. PTSD involves persistent psychological distress following exposure to a traumatic event such as exposure to actual or threatened death, injury, or sexual violation 3,4.

Its symptoms include:

  • Recurring intrusive memories, thoughts, and dreams associated with a traumatic event.
  • Avoidance of places, people, and situations that remind an individual of the event.
  • Abnormal arousal such as feeling anxious, agitated, or experiencing sleep disturbances.
  • Cognitive or mood disturbances, including impaired memory, feeling depressed, and a diminished motivation to participate in or derive pleasure from enjoyable activities.

Because of these symptoms, individuals who suffer from PTSD have difficulty functioning in society and maintaining social relationships. They are also at a greater risk for suicide and suicidal thoughts, particularly in veteran populations 5,6. Current therapies for PTSD are intensive (requiring multiple follow-ups), ineffective for many (~30%), and have potential for unwanted side effects 7,8. Therefore, it is critical to explore new and more effective forms of treatment for the general public or vulnerable populations who benefit even less from traditional treatments 9.

Cannabis and PTSD

There has been considerable research conducted over the last 20 years demonstrating the involvement of the endogenous cannabinoid system (ECS; the system in the brain/body through which cannabis exerts its effects) in the regulation of stress, anxiety, and PTSD 10,11,12. Therefore, when cannabinoids like THC and CBD are consumed, they act on the ECS and can potentially modify stress, anxiety, and PTSD symptoms, if given at the right dose.

There is some evidence that CBD reduces anxiety 13-15 and improves mood 16-18, likely through actions on serotonin receptors, a common target of anti-depressants. THC has been found to improve sleep apnea 19 and could be useful for promoting safety learning 11,20 (learning that something previously associated with a traumatic event, such as loud noises, is no longer predictive of harm), something that is typically impaired in individuals with PTSD.

Research also indicates a positive correlation between PTSD symptom severity and cannabis use 8. This relationship may be explained by the fact that individuals with PTSD report that cannabis alleviates their symptoms (such as negative mood, anxiety, and sleep disturbances) and improves factors that contribute to quality of life (e.g., social relationships) 21-23.

Cannabis holds great potential for treating PTSD in individuals considered to be low risk for substance abuse and can be considered in instances where traditional therapies are ineffective or as an adjunct to an existing treatment plan. While some studies show that PTSD symptoms can improve with cannabis use, it should be noted that others did not find a relationship 24, and there is a need for controlled clinical trials on cannabis’ use in the treatment of PTSD. As with all medications, patients considering cannabis as a treatment for anxiety and mood disorders should first speak to a health care practitioner to determine the options that are right for them and an appropriate treatment plan.



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  2. Van et al. (2008). Post-traumatic stress disorder in Canada. CNS Neurosci. Ther. 14:171–181.
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  4. Post-Traumatic Stress Disorder. National Institute of Mental Health.
  5. Pompili et al. (2013) Posttraumatic stress disorder and suicide risk among veterans: a literature review. J Nerv Ment Dis 201:802-12.
  6. D’Aliesio et al. (2016). Suicide toll reveals how system failed Canada’s soldiers and veterans. The Globe and Mail,
  7. Bradley et al. (2005). A multidimensional meta-analysis of psychotherapy for PTSD. American journal of Psychiatry 162: 214-227.
  8. Mizrachi et al. (2016) Cannabinoids and post-traumatic stress disorder: clinical and preclinical evidence for treatment and prevention. Behav Pharmacol 27: 561-9
  9. Watts et al. (2013). Meta-Analysis of the Efficacy of Treatments. J Clin Psychiatry, 74: e541-e550.
  10. Hill and Gorzalka (2009). The endocannabinoid system and the treatment of mood and anxiety disorders. CNS & Neurological Disorders-Drug Targets (Formerly Current Drug Targets-CNS & Neurological Disorders) 8: 451-458.
  11. Hill et al. (2018). Integrating endocannabinoid signaling and cannabinoids into the biology and treatment of posttraumatic stress disorder. Neuropsychopharmacology 43: 80.
  12. Bitencourt and Takahashi (2018) Cannabidiol as a Therapeutic Alternative for Post-traumatic Stress Disorder: From Bench Research to Confirmation in Human Trials. Front. Neurosci 12:502.
  13. Bergamaschi, M. M., Queiroz, R. H. C., Chagas, M. H. N., De Oliveira, D. C. G., De Martinis, B. S., Kapczinski, F., … & Martín-Santos, R. (2011). Cannabidiol reduces the anxiety induced by simulated public speaking in treatment-naive social phobia patients. Neuropsychopharmacology, 36(6), 1219.
  14. Zuardi, A. W., Cosme, R. A., Graeff, F. G., & Guimarães, F. S. (1993). Effects of ipsapirone and cannabidiol on human experimental anxiety. Journal of Psychopharmacology, 7(1_suppl), 82-88.
  15. Zuardi, A. W., Rodrigues, N. P., Silva, A. L., Bernardo, S. A., Hallak, J. E., Guimarães, F. S., & Crippa, J. A. (2017). Inverted U-shaped dose-response curve of the anxiolytic effect of cannabidiol during public speaking in real life. Frontiers in pharmacology, 8, 259.
  16. Zanelati, T. V., Biojone, C., Moreira, F. A., Guimaraes, F. S., & Joca, S. R. L. (2010). Antidepressant‐like effects of cannabidiol in mice: possible involvement of 5‐HT1A receptors. British journal of pharmacology, 159(1), 122-128.
  17. Linge, R., Jiménez-Sánchez, L., Campa, L., Pilar-Cuéllar, F., Vidal, R., Pazos, A., … & Díaz, Á. (2016). Cannabidiol induces rapid-acting antidepressant-like effects and enhances cortical 5-HT/glutamate neurotransmission: role of 5-HT1A receptors. Neuropharmacology, 103, 16-26.
  18. Sartim, A. G., Guimarães, F. S., & Joca, S. R. L. (2016). Antidepressant-like effect of cannabidiol injection into the ventral medial prefrontal cortex—Possible involvement of 5-HT1A and CB1 receptors. Behavioural brain research, 303, 218-227.
  19. Carley, D. W., Pavlovic, S., Janelidze, M., & Radulovacki, M. (2002). Functional role for cannabinoids in respiratory stability during sleep. Sleep, 25(4), 388-395.
  20. Passie, T., Emrich, H. M., Karst, M., Brandt, S. D., & Halpern, J. H. (2012). Mitigation of post‐traumatic stress symptoms by Cannabis resin: A review of the clinical and neurobiological evidence. Drug testing and analysis, 4(7-8), 649-659.
  21. 21. Yarnell S (2015). The use of medicinal marijuana for posttraumatic stress disorder: a review of the current literature. Prim Care Companion CNS Disord 17. doi: 10. 488/pcc.15r01786.
  22. Betthauser et al. (2015). Use and effects of cannabinoids in military veterans with posttraumatic stress disorder. American Journal of Health-System Pharmacy, 72(15), 1279-1284.
  23. Smith et al. Medical cannabis use in military and police veterans diagnosed with post-traumatic stress disorder (PTSD) Journal of Pain Management 10:397-405
  24. Johnson et al. (2016). Mental health symptom severity in cannabis using and non-using Veterans with probable PTSD. Journal of affective disorders 190: 439-442.