What evidence supports the beneficial effects of CBD?
For anyone who’s interested in either the science behind how CBD works on these afflictions or wants to verify the validity of these claims, I cannot recommend enough Pisanti et al.’s 2017 review of the potential therapeutic applications. They do an exceptionally thorough job of vetting dozens of independent studies and summarising the main findings. I’m going to be referring heavily to their review over the course of this post, and hopefully summarising it into a bite-size and easily understandable synopsis.
Firstly I’d like to discuss anxiety, a topic I find most interesting because of a seeming contradiction in the literature. A paper by Arndt and Wit (2017) found zero correlation between CBD use and mitigation of anxiety in healthy volunteers. The authors do admit that perhaps their testing methods weren’t thorough enough to induce a strong enough anxiety response and that perhaps CBD has a greater effect on people with higher anxiety levels. This makes sense in context with other studies (Bergamaschi et al, 2011, Blessing et al, 2015, Schier et al, 2012) that found that CBD has a significant effect on reducing anxiety in people suffering from anxiety disorders. The overall conclusion seems to be that lower doses (approximately 10mg/kg) have the greatest impact on anxiety. Thus we can make a link here that people who suffer from high levels of anxiety get more benefit than healthy people that are exposed to anxiety-inducing situations.
Now I’d like to look at neurodegenerative disorders like Alzheimer’s, MS and Parkinson’s. These diseases are characterised by a loss of neurons, the cells in your nervous system that transmit signals from your brain to all parts of your body. As you lose these neurons your body’s ability to function properly is reduced. CBD can potentially be an effective treatment for these afflictions due to its neuroprotective, anti-inflammatory and antioxidant effects. Zuardi et al (2009) reported significant improvements in Parkinson’s patients that were treated with CBD alongside their usual therapy, in addition to reduced psychotic symptoms.
As of 2017 there were no clinical trials studying the effects of CBD alone in the treatment of Multiple Sclerosis (MS), but previous literature suggests that its anti-inflammatory effects and ability to influence the immune system could prove effective in management of the major aspects of MS (Kozela et al, 2011 and Mecha et al, 2013).
One therapeutic use of CBD that has already gained a notable reputation is for the treatment of epilepsy and similar seizure disorders. Current anti-convulsive drugs are insufficient for the demand, as many have unwelcome side-effects. In addition, up to 30% of epilepsy sufferers have inadequate control of their seizures with current drugs (Kwan and Brodie, 2000). Though the method through which CBD moderates seizure frequency and intensity is unknown, its positive effect for epileptics is undeniable. Devinsky et al. (2016) found that in 162 patients with severe, treatment-resistant epilepsy, CBD in conjunction with their usual drugs led to a median reduction in monthly seizures of 36.5%. Some adverse effects were present like sleepiness, fatigue and diarrhoea, but compared to the side-effects of some current anti-epilepsy drugs these were considered acceptable.
Finally, I want to discuss cancer. This could be a whole post unto itself, but I’ll only examine the anti-tumour properties of CBD in regards to cancer as whole, rather than how it affects each type of cancer specifically. Section 3.7 of Pisanti et al.’s (2017) review refers to almost a dozen papers all documenting the potential of cannabinoids for preventing the proliferation and spread of cancerous cells. CBD has been put forward as the best candidate for further research for two main reasons: its lack of undesired psychoactive properties in comparison to THC, and the relative ease with which it can be produced compared to similar cannabinoids like CBG (cannabigerol). Some studies (Scott et al. 2014) have proposed that a combination of CBD and THC could have the greatest benefit, due to CBD’s ability to mitigate the undesired effects of THC.
There are obviously many therapeutic effects I’ve had to leave out for the sake of brevity. As I mentioned at the start of this post, I highly recommend that anyone who is interested in these applications for CBD should read Pisanti et al.’s review. Despite the concise nature of this summary, I hope that I’ve imparted some of the magnitude of CBD’s potential for alleviation and treatment of a wide range of afflictions and diseases.
Pisanti et al. (2017) https://www.sciencedirect.com/science/article/pii/S0163725817300657?via%3Dihub