High Time Medical Marijuana Was Taken Seriously
Marijuana is associated with hallucinogenic effects and an altered state of consciousness. The dried leaves and flowers of cannabis sativa have also long been understood to have medicinal properties. Marijuana was first used in nineteenth century European medicine to combat pain, muscle spasms and convulsions associated with tetanus, rheumatism and epilepsy.1 However, the drug is not without risk.
Marijuana contains a mix of cannabinoids. One of them, Cannabidiol (CBD), has calming, sedative effects and is responsible for much of marijuana's benevolent “Summer of Love” reputation for a gentle euphoria. Regular marijuana use, however, is linked to dependence, with physical, mental and behavioural consequences because it also contains delta-9-tetrahydrocannabinol (THC), the chemical responsible for the psychological response.
More potent forms of marijuana bred to be high in THC at the expense of CBD are linked with triggering and exacerbating psychotic illnesses, including schizophrenia. Marijuana smoke contains many of same carcinogenic hydrocarbons as tobacco smoke. Although the evidence is not unanimous, a link to cancer from the way people smoke the drug or from genetic cause cannot be completely ruled out.
Given these significant drawbacks, it comes as a surprise that marijuana is increasingly being legalised for medical use. However, the medical version of marijuana - in the form of pills or mouth sprays-– combines cannabinoids CBD and THC extracted from the whole, unprocessed cannabis plant in a specific ratio.
CBD and THC interact with G protein-coupled cannabinoid 1 (CB1) receptors in the central nervous system giving analgesic, euphoric and anticonvulsive effects. CBD has no effect on the mind or behaviour but it mitigates the psychoactive and addictive potential of the THC component, leading to a lower probability of developing dependence.
Medicinal cannabinoids supplement the endocannibinoids that are produced naturally in our bodies and play a role in regulating the senses, memory, awareness and pain. Despite its frequent classification as an illicit drug, the beneficial properties of marijuana should not be overlooked - a 20mg dose of THC is a more effective analgesic than 120mg of codeine.2 Opioid medications, such as codeine, are problematic when used for treating chronic pain, due to their adverse side effects and potential for abuse.3
Medical marijuana is increasingly held to have a role in therapeutic management of patients with chronic pain, epilepsy, diabetes and cancer. The muscle relaxant and analgesic effects of THC in cases of multiple sclerosis are well documented.4
Preclinical and clinical trials with marijuana and numerous other medical conditions are underway. More and larger studies are needed to understand the adverse effects associated with therapeutic use - such as nervous system and psychiatric disorders, gastrointestinal disorders, and vascular and cardiac disorders - especially in vulnerable populations.5,6
Many EU countries and states in the U.S. have already granted patients the use of marijuana-based therapies.7 Prescription medication is classified separately from cannabis, allowing for regulatory approval, while bans on the illicit version are maintained.
The long half-life of the human body's elimination of cannabinoids and their metabolites means drug screening can be positive weeks after use. Legitimate medical use should not be presumed an acceptable explanation for a confirmed positive laboratory report of marijuana without a careful cross-check of medical and prescription history.
- O’Shaughnessy, WB., (1843) On the preparations of the Indian Hemp, or Gunjah (Cannabis Indica): Their effects on the animal system in health, and their utility in the treatment of tetanus and other convulsive diseases. Prov Med J Retrosp Med Sci, 123, 363-369.
- Campbell, FA., et al., (2001) Are cannabinoids an effective and safe treatment option in the management of pain? BMJ : British Medical Journal. 2001;323(7303):13.
- Hayes MJ & Brown MS., (2014) Legalization of medical marijuana and incidence of opioid mortality, Jama Intern Med 2014;174(10):1673-74.
- Whiting, PF., et al., (2015) Cannabinoids for medical use, a systematic review and meta-analysis, J Amer Med Ass, 313, 2456-2473.
- Wang, T., et al. (2008). Adverse effects of medical cannabinoids: a systematic review. CMAJ. 178: 1669-1678.
- Volkow, ND et al., (2106) Effects of cannabis use on human behaviour, including cognition, motivation, and psychosis : a review, JAMA Psychiatry. 2016;73(3):292-297.
- Office of National Drug Control Policy (2016), Marijuana Resource Center: State laws related to marijuana. https://www.whitehouse.gov/ondcp/state-laws-related-to-marijuana (accessed March 2016).