White Coat, Black Art·Q&A

CBD oil is seen as a magic elixir — but the jury is still out on its medical effectiveness

CBD is being touted as a treatment for everything from insomnia to pain. Almost a year in the legalization of cannabis, we look at what medical evidence exists around CBD, and what still remains unknown.

Two experts walk us through the science and the mysteries behind cannabidiol

Medical cannabis plantsgrowing in a Niagara greenhouse, June 26, 2019. White Coat, Black Art spoke with two experts about the scientific evidence supporting CBD as a medicine. (Jeff Goodes/CBC)

Cannabidiol, better known as CBD, has been touted as a treatment for everything from insomnia to aches and pains.

CBD is one of the hundreds of chemical substances called cannabinoids derived from cannabis plants. However, it does not produce the same psychoactive effects as its sister compound, THC, according to Health Canada.

Typically found in oil or capsule form, CBD is legal in Canada when sold in compliance with the Cannabis Act. But finding reliable medical information about it can be difficult. 

White Coat, Black Art asked two experts about what information exists about CBD, and what questions remain unanswered.

What is the most reputable source for CBD oil?

3 years ago
Duration 1:06
Health Canada plays an important role in regulating CBD producers

Maddie Brown, a registered practical nurse and cannabis consultant based in Ottawa, helps patients with medical cannabis prescriptions navigate the system and understand how CBD works. M-J Milloy is a research scientist at the British Columbia Centre on Substance Use in Vancouver, and a professor of cannabis science at the University of British Columbia.

Here is part of their conversation with White Coat, Black Art host Dr. Brian Goldman.

Preliminary findings

M-J Milloy, a professor of cannabis science at the University of British Columbia, says the prohibition of cannabis until recently means there hasn't been the kind of rigorous testing needed to determine if CBD is an effective treatment for many ailments. (Rafferty Baker/CBC)

M-J, how much hard evidence is there regarding CBD's medical effectiveness?

Milloy: As with a lot of cannabis science, what we're facing as scientists is good, hard evidence from preliminary studies, primarily among rats and other sorts of model organisms. For example, with joint pain, we do know that there have been some experimental studies showing that topical applications of CBD are effective at lowering inflammation and apparently causing reductions in functional pain. The problem is, because of cannabis prohibition, which of course lasted from the early 1900s all the way up until last year, us scientists in clinical research have really not been able to do the sort of clinical trials needed to figure out if these things are effective in humans, what the dose might be, and what some of the risks and benefits of CBD-based therapies are.

What are some of the most promising areas of study right now when it comes to CBD?

Milloy: Pain and related conditions [are] very promising. There is strong evidence, as I said, from rats, that there [are] beneficial biological interactions between CBD and disease. In my area — addiction medicine and hopefully, treating people with CBD who are suffering from substance use disorders — there is also some very good preliminary evidence in humans that CBD might help people who are trying to lower or eliminate their use of addictive substances, and in particular, opioids, which gives us a lot of hope to address the overdose crisis. 

But really, while we do have these preliminary findings, CBD really hasn't faced the sort of rigorous testing and placebo-controlled clinical trials that we need to really conclude that it is an effective therapy.

Maddie Brown, a registered practical nurse and cannabis consultant based in Ottawa, says CBD has been life-changing for her patients who suffer from inflammatory pain conditions. (Submitted by Maddie Brown)

Do you agree with that Maddie?

Brown: I totally do. I'll be the first person to stand up and say, 'Hey, it looks like it didn't work after all. At least we studied it and we have that conclusively.' But that's not what all my anecdotal reports and signs are indicative of. I have not had any of my pain patients be disappointed with CBD once they've figured out what method of administration works in their particular case, and for me that's hugely reassuring.

THC is a totally different area. It has totally different effects and totally different risks and rewards. But CBD has been hugely life-changing for my patients who suffer from inflammatory pain conditions, back pain, muscle pain, joint pain. I have a lot of different athletes who are using it for concussion syndrome, for the nausea associated with concussion syndrome.

M-J, when you hear Maddie's enthusiasm, how do you react to that?

Milloy: It really is something that we need to pay careful attention to. The reality is, a lot of folks who are using cannabis therapies, whether it's for pain, for arthritis, for mood disorders, they're facing conditions that are not well treated by current clinical approaches that may have many side effects and adverse events. So certainly if there's another treatment out there which provides more comfort, more symptom relief for individuals, then we have to test it.

CBC Explains: What is CBD?

3 years ago
Duration 2:21
We answer five big questions about Cannabidiol — better known as CBD oil — which some say has unique health benefits.

CBD and young people an area of 'active research'

A technician sprays water on marijuana plants at the medical marijuana facility in Richmond, B.C., on March 21, 2014. Maddie Brown, a cannabis consultant and registered practical nurse in Ottawa, says there is a lack of data around how CBD from cannabis affects children and teens. (Darryl Dyck/The Canadian Press)

M-J Milloy, what do we know about CBD and its uses in children and teenagers?

Milloy: The one clinical trial that we do have for CBD and pediatric patients was for individuals suffering from Dravet syndrome, a rare genetic condition in children that causes epileptic seizures and brain dysfunction.The good news is that there was quite clear dosing, so people were exposed to about 20 milligrams of CBD per kilogram of body weight. There were a number of adverse events, which were more common among the people who were in the CBD group. Some people were suffering from diarrhea, from vomiting, from fatigue, and events of that sort of nature. This was a relatively high dose of CBD I think, and for people with a very specific condition.

Unfortunately that's really all we know from the clinical trial data about CBD and young people. But certainly it is an area of very active research.

Maddie, how many of your clients are children or teens?

Brown: I would say about 150 of my patients have been in the pediatric population. A lot of my pediatric patients are cancer patients. So these are kids that are ... palliative in nature, and parents, rather, are looking for symptom management. They're looking for more natural options just to keep their children comfortable.

I'm not at the point where I'm comfortable helping people with pediatric mental health stuff. As a nurse, I kind of have to step back and wait for, like M-J is saying, just more conclusive studies and data pertaining to kids. Until then, it's a huge risk for anybody in the health-care industry to be involved in it. There's just not enough data there yet.

Be wary of drug interactions

CBD oil is seen displayed at The Cannabis World Congress & Business Exposition (CWCBExpo) trade show in New York City, New York. (Mike Segar/Reuters)

M-J … [should we be concerned about] CBD interacting with other medications?

Milloy: Even though something is natural or comes from the natural world, it does not mean that it does not carry risks. [With] other medications that people are often taking for the very same reasons that they might be trying CBD⁠ — in terms of having anxiety or pain ⁠— there is good theoretical evidence that CBD could affect the metabolism of things like anti-depressants, like opioids and benzodiazepines. And these are obviously very serious medications with very serious risks, and so it's very concerning.

Maddie, what drug interactions are you the most concerned about?

Brown: I'm definitely most concerned about blood thinners, actually. CBD can make Coumadin [a blood thinning medication] more potent. So if your Coumadin is more effective than it technically should be, your blood is too thin and you're going to be brushing your teeth or going to the washroom and noticing small amounts of blood.

Q&A edited for clarity and length.


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