Cannabis is everywhere at the moment – being legalized left, right and centre across states of the US and Canada. Not only is there a buzz around the legal use of this plant for recreational purposes, but also a couple of its derivatives, CBD (cannabidiol) and THC (delta‐9‐tetrahydrocannibinol). THC is the main psychoactive component of cannabis, but CBD is thought to have many possible applications as a medicinal drug, without the associated cannabis high.
This week there have been at least three cannabis-related news stories on the BBC, but here I would like to highlight two of them. These are the headlines:
In the first one, “CBD oil: have the benefits been overstated?” the journalists make a very important point about how people buying into this new craze and expecting a miracle cure are probably going to be disappointed. Unregulated products have huge variations in the amount of CBD they contain. Some contain none. In the article, a recent review from the University of Nottingham is mentioned – let’s check it out and see what it has to say.
The authors of this study, Sophie Millar and colleagues, carried out a type of analysis called a systematic review (linked here). Using this technique, all the clinical trials using CBD were gathered together to give a big picture of how the drug works. The main questions the researchers wanted to answer were: 1) What illnesses have been tested for treatment with CBD? 2) What are the best doses?
They found 35 clinical trials testing CBD with a total of 1223 people taking part (quite small numbers in the world of medicine). Eleven trials looked at CBD use for epilepsy where significant improvements were seen when CBD was given as an add-on to existing medications. Seven trials looked into CBD use in patients with schizophrenia with mixed results; some reported improvement with CBD, and others reported no change. Results were also mixed in Parkinson’s disease patients, with some symptoms being made better, and some worse. People with Huntington disease showed no change in symptoms after using CBD, neither did those with diabetes or Crohn’s disease. Chronic pain was not reported to be improved.
Interestingly, across a few of the trials, the participants reported a reduction in general anxiety with use of CBD.
Now to the second question… dose.
The clinical trials used doses that ranged from less than 1 mg per kilo of body weight per day, right up to 50 mg. It seems low doses can be effective for some illnesses, but not for others – it really depends on what you want to treat.
Epilepsy is the only disease where the most thorough research into CBD use has been carried out. And this leads on to the second article: “Lack of evidence holding back cannabis medicines”.
Well, given the review above, which highlights how little we know about CBD dosing and the diseases it could be used to treat, I am pretty pleased that this is the case. Yes, more research needs to be carried out quickly so that people who may benefit from CBD can get it as soon as possible, but it would be crazy for health authorities to be handing it out like candy when there are so many unknowns. For instance, we still don’t know how much CBD actually gets through the stomach and into the blood when you eat it or take a pill. How much do you get into your blood if you vape it? No idea either. And what about in children vs. adults? Pregnant women? Who knows.
The good news is that CBD is already being prescribed to help people with epilepsy, so research is going in the right direction. However, as the BBC article highlights, don’t be surprised if your CBD latte does diddly squat.
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