A recent study found that low concentrations of cannabidiol (CBD) can increase the intoxicating effects of tetrahydrocannabinol (THC) and that high concentrations of CBD alone can provoke slight levels of intoxication. These discoveries, published this January in the journal European Archives of Psychiatry and Clinical Neuroscience, challenge previously held ideas about CBD—that it curtails some of the intoxicative effects of THC and that CBD isn’t intoxicating in itself. If these findings prove to be correct, they offer valuable information for the makers of medicinal cannabis products as they consider appropriate dosages.
The study, conducted by a team of Australian researchers, asked 36 participants to vaporize varying quantities of CBD and THC, both independently and in conjunction. At intervals of one week, the participants vaped a placebo, a standard dose of 8mg of THC, a combination of THC and CBD similar to that found in cannabis products (8mg and 4mg, respectively), a combination of the two cannabinoids featuring a high dose of CBD (12mg THC, 400mg CBD), and finally a dose of 400mg CBD alone. Researchers gauged levels of intoxication based on self-reports as well as blood samples and blood pressure data from the participants.
Prior to this study, conventional wisdom regarding CBD held that it subtly negates the elevated mood produced by THC. In other words, people thought combining CBD with THC would get you less stoned than if you consumed only THC. Researchers found that this holds true when the amount of CBD consumed is very high (as in the 12mg THC, 400mg CBD mix). But when the dosages of CBD were lowered to a level more commonly found in cannabis products, participants’ subjective levels of intoxication were greater than those produced by THC alone, especially in infrequent cannabis users. In other words, a lot of CBD can make the sensation of being stoned less intense, but a little bit of CBD can actually amp up the intoxicating effects of THC.
“The finding that low doses of CBD may potentiate effects of THC has significant implications for consideration of proportions of THC and CBD that may be recommended within plant matter,” the researchers noted. “With cannabis increasingly being used for medicinal purposes, it is important to ensure that harms are minimized in favor of boosting therapeutic properties.”
The study also published findings that challenge the idea that CBD doesn’t produce intoxication. Based on participants’ subjective reports, researchers concluded that, “CBD showed some intoxicating properties relative to placebo.” This is the first time that intoxication via CBD has been published in the scientific literature around cannabis, and, as CBD is becoming more and more common, it could be important knowledge for some CBD users. The study explains that, “While intoxication per se is not necessarily harmful overall, it is not welcome by many clinical patients, and it may be harmful in situations such as driving under the influence of cannabis.”
The research does come with at least one caveat. The lead researcher, Dr. Nadia Solowij, has published more than 100 studies on cannabis, and her findings regularly paint cannabis in a negative light. (We looked at more than 20 studies she co-authored, and the findings were all negative.) This arguably suggests a potential for bias that should be taken into account. Regardless, the current study still provides further evidence that society needs continued and well-funded research into these unique substances as they continue to be integrated into our culture.