CBD vs. THC: Why Is CBD Not Psychoactive?
When learning about the inner workings of CBD and THC, many people get confused and start asking questions: Why is it that THC is a psychoactive, and CBD isn’t? How can a cannabinoid so profoundly alter the mind, while the other apparently has no effects of the sort?
When we talk about psychoactivity and cannabis, we’re dealing with CB1 receptors, which are located mostly in the central nervous system and the brain. The difference between THC and CBD comes down to how each of the substances interacts with the CB1 (cannabinoid 1) receptor. THC binds very well with this type of receptor, while CBD doesn’t have a that much binding affinity for it – that’s the main difference between the two.
A good way to think about it is imagining an electrical plug connected to a wall socket. THC molecules have a perfect shape to connect with CB1 receptors. As soon as the connection happens, THC activates, stimulating the receptors.
The effect that THC causes are due to the fact it mimics anandamide, a neurotransmitter known as “the bliss molecule” for its effects. Anandamide is an endocannabinoid and activates CB1 receptors. Research with animal studies taught us that the substance increases appetite and increases pleasure from eating food. It is also partially responsible for the rewarding effects of exercising, such as the “runner’s high.” Anandamide plays a role in motivation, memory, and pain as well. THC resembles anandamide very carefully, activating CB1 receptors and producing the aforementioned blissful feelings.
CBD, on the other hand, isn’t that much of a good fit for CB1 receptors. In fact, it is considered an antagonist of the CB1 agonists. That means that it doesn’t directly suppress or activates CB1 receptors – instead, it reduces the CB1-activating qualities of cannabinoids such as THC. This is to say that, when ingesting CBD and THC, the THC stimulates CB1 receptors, while CBD acts as some modulating influence on THC. As explained by Martin Lee, Project CBD’s co-founder, the substance opposes the THC action at CB1 receptors, muting the THC’s psychoactive effects.
How does that work in practice? Well, let’s say you vaporize some cannabis flower that has 24 percent THC. If the flower contains 0.2 percent CBD, there will be almost no interference, and the THC will excite CB1 receptors freely. You are likely to feel an intense high, and perhaps experience some adverse effects of THC, such as a strong feeling of paranoia. Should you, instead consume cannabis that has the same amount of THC, but 5 percent CBD, the CBD will likely have a dampening effect on your high. You’ll still feel it, but not that strongly, and you probably won’t get paranoia.
This psychoactivity difference has some serious political implications. Project CBD’s founders have noticed that many mistakenly label THC as a “wrong cannabinoid” and CBD as a “useful cannabinoid.” Many legislators passed laws in Southern states that limit consumption to CBD only, preventing the use of its psychoactive counterpart, but Raphael Mechoulam, a pioneering cannabis researcher, often speaks of the entourage effect – which is the idea that terpenes and cannabinoids work better together than separately. GW Pharma’s Sativex, for instance, is a drug for muscle spasticity related to MS – it’s approved outside the U.S. and contains nearly a 1:1 THC-to-CBD ratio.
As researchers learn more and more about CBD and other substances in the treatment of conditions such as MS, we might have been able to dose CBD more accurately, in combination with such compounds.
Fuss J, Steinle J, Bindila L, PDF
Mahler SV, Smith KS, Berridge KC. PDF
Englund A, Morrison PD, PDF