Cannabidiol (CBD) is one type of natural compound out of over 100 chemical compounds that are known as cannabinoids [1]. Cannabis plants, the source of cannabinoids, are called either hemp or marijuana, dependant of their level of one cannabinoid, in particular, tetrahydrocannabinol (THC). THC is associated with the psychoactive effects seen with cannabis use, whereas CBD is not [1]. There has been research that explores the potential health benefits of CBD and you may have noticed a surge in the popularity of CBD products in the last few years. However, it should be noted that while there have been many studies in the past decade, the research around CBD is limited and speculative as the majority were done with animals only [1]. CBD has been trialed in several disorders and preliminary evidence suggests improvements in spasticity, pain, sleep disturbances, and mobility in multiple sclerosis, as well as alleviating anxiety symptoms in social phobia [2]. Research also suggests CBD products may be beneficial in the treatment of depression, anxiety, cognitive impairment, as well as discomfort before public speaking [1].
In the literature, more than 65 discrete molecular targets have been reported for CBD which spans ion channels, receptors, transporters, and enzymes [3]. However, a limited number of such represent plausible targets for the drug’s action in neurological disorders. Those that hold sufficient evidence for involvement in therapeutic effects in neurological disorders include voltage-dependant anion channel 1, G protein-coupled receptor 55, and CaV3.x, among others [3]. These targets are associated with either the regulation of, or responses to changes in intracellular calcium levels and are unlikely to act through the endocannabinoid system [3]. Before large-scale human trials begin taking place, it is said a better understanding of how CBD acts on the human brain is desirable [2].
The benefits of CBD in treating depression are believed to be exercised through its positive effect on serotonin receptors in the brain, as low serotonin levels are linked to depression. It should be noted that while CBD does not boost the levels of serotonin in the brain, it may affect how the brain’s chemical receptors respond to existing serotonin [1]. Depression and anxiety commonly occur together, and the most reported use of recreational CBD is the treatment for anxiety [4]. In a study where participants with social anxiety disorder were given a one-time oral dose of 600mg of CBD one hour before speaking publicly, the results showed a reduction in self-reported anxiety compared to a control group [5]. A review of 11 trials found that when CBD is taken one hour before an anxiety-inducing event, a compilation of reports found that nearly 80% of patients saw reductions in their anxiety within a month [4]. However, larger trials are needed to definitively confirm the association between CBD and improvements in anxiety.
Many medications for pain are by nature highly-addictive, and so there is a demand for alternative therapy options. Several small and early studies suggest that while CBD is not effective in managing short-term, acute pain, it may be of interest when managing long-term, chronic pain [4]. In a study where 97 chronic pain patients swapped their opioid prescriptions for a daily dose of 30mg of CBD for one year, results showed that CBD improved the quality of life of 94% of the participants and reduced or eliminated opioid use in 53% of participants [7]. However, another study found that while CBD effectively reduced chronic pain by 1.5 points on an 11-point pain scale, this did not bring about a clinical difference in patient outcomes and so larger and more highly powered studies are again warranted [8].
The relationship between CBD and sleep appears to be dose-dependent. Lower doses seem to be stimulating, while larger doses appear to have a sedative nature and may improve sleep and wakefulness during the night [9, 10]. It should be noted that the scientific evidence behind these claims is limited and the mode of action has not been elucidated, so once again further trials are needed to solidify our understanding of this.
So, is the hype warranted? We would say yes. While the science is not solid just yet, it does look promising. CBD products are becoming increasingly popular as a treatment for a range of health issues and new research is being published every year. It is expected that until researchers better understand the effects of CBD and its potential benefits or concerns, information about how to best use the CBD products that are now on the market will continue to shift. While studies show the compound is safe, it should be noted that it is possible CBD may interact with some medication and so you should speak to your healthcare provider about what you are considering using CBD in combination with.
Mia Georgiou
Bibliography:
[1] Healthline. 2019. CBD for Depression: What Are the Benefits?. [online] Available at: <https://www.healthline.com/health/cbd-for-depression#takeaway> [Accessed 18 March 2021].
[2] Pretzsch, C., Freyberg, J., Voinescu, B., Lythgoe, D., Horder, J., Mendez, M., Wichers, R., Ajram, L., Ivin, G., Heasman, M., Edden, R., Williams, S., Murphy, D., Daly, E. and McAlonan, G., 2019. Effects of cannabidiol on brain excitation and inhibition systems; a randomised placebo-controlled single dose trial during magnetic resonance spectroscopy in adults with and without autism spectrum disorder. Neuropsychopharmacology, 44(8), pp.1398-1405.
[3] Ibeas Bih, C., Chen, T., Nunn, A., Bazelot, M., Dallas, M. and Whalley, B., 2015. Molecular Targets of Cannabidiol in Neurological Disorders. Neurotherapeutics, 12(4), pp.699-730.
[4] Michelle Darian, R., 2020. The Science Behind CBD’s Effects on the Brain and Body. [online] Blog.insidetracker.com. Available at: <https://blog.insidetracker.com/science-behind-cbd-effects-brain-body> [Accessed 22 March 2021].
[5] Bergamaschi MM, Queiroz RHC, Chagas MHN, de Oliveira DCG, De Martinis BS, Kapczinski F, et al. Cannabidiol reduces the anxiety induced by simulated public speaking in treatment-naïve social phobia patients. Neuropsychopharmacol Off Publ Am Coll Neuropsychopharmacol. 2011 May;36(6):1219–26.
[6] Linares IM, Zuardi AW, Pereira LC, Queiroz RH, Mechoulam R, Guimarães FS, et al. Cannabidiol presents an inverted U-shaped dose-response curve in a simulated public speaking test. Rev Bras Psiquiatr Sao Paulo Braz 1999. 2019 Feb;41(1):9–14.
[7] Capano A, Weaver R, Burkman E. Evaluation of the effects of CBD hemp extract on opioid use and quality of life indicators in chronic pain patients: a prospective cohort study. Postgrad Med. 2020 Jan;132(1):56–61.
[8] Lynch ME, Campbell F. Cannabinoids for treatment of chronic non-cancer pain; a systematic review of randomized trials. Br J Clin Pharmacol. 2011 Nov;72(5):735–44.
[9] Babson KA, Sottile J, Morabito D. Cannabis, Cannabinoids, and Sleep: a Review of the Literature. Curr Psychiatry Rep. 2017 Apr;19(4):23.
[10] Zuardi AW. Cannabidiol: from an inactive cannabinoid to a drug with wide spectrum of action. Rev Bras Psiquiatr Sao Paulo Braz 1999. 2008 Sep;30(3):271–80.
