Your Brain on Food

How chemicals control your thoughts and feelings.

Is CBD Better Than THC?

Why are growers breeding marijuana plants with higher levels of cannabidiol?

Marijuana typically contains 2%-5% delta-9 tetrahydrocannabinol (THC). However the plant also contains about many other cannabinoid-based compounds, including cannabidiol (CBD).  Recent Internet ads have made claims that “CBD can cure arthritis, multiple sclerosis, chronic pain, schizophrenia, and [most recently] epilepsy.” Somehow one particular component of marijuana plant has become much more popular than all of the 60 (at least) other biologically active molecules that have been isolated from this plant. Cannabidiol is the main non-psychotropic cannabinoid present in the Cannabis sativa plant. Somehow this one particular component of marijuana plant has become much more popular than all of the sixty (at least) other biologically active molecules that have been isolated from this plant. Is CBD better than THC? The answer is—maybe. 

Why are people so excited about CBD? Why are growers breeding marijuana plants with significantly higher levels of CBD? The answer lies in unpacking a series of complex truths, making distinctions between what is known and what is not known, and dispelling some false claims. 

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The human brain possesses a pair of protein receptors that respond to a pair of endogenous marijuana-like chemicals. These receptors are incredibly common and are found throughout the human brain. When a person smokes marijuana all of the various chemicals in the plant are inhaled, ultimately, into the brain where they find and bind to these receptors similar to a key fitting into a lock. Which receptors are affected, and what parts of the brain are involved, differs for just about everyone, depending upon their genetic make-up, drug-taking history and expectations regarding the experience; the last factor being commonly known as the placebo effect.

In addition, the chemicals inhaled into the brain also interact with a complex array of other neural systems; these interactions also contribute to the overall psychoactive experience such as the ability of marijuana to reduce anxiety or produce euphoria or induce “the munchies.” My own research has demonstrated the positive effects of stimulation of the endogenous cannabinoid neural system in the aging brain.  [ohio-state.edu/wenk]

Both CBD and THC are capable of interacting with this complex variety of proteins. However, and this is where things get interesting, they do not do so with the same degree of effectiveness.  Scientists have shown that THC is over one thousand times more potent than is CBD! The dose of THC the brain required in order to experience a typical “high” is a thousand times lower than a dose of CBD.  This chemical property of CBD has led to the accurate claim that CBD does not make one feel “high.” A person would need to consume 1,000 “joints” of the genetically modified CBD-marijuana plant to get high. However, the low potency of CBD may also indicate that, by itself, it offers limited clinical benefits. Currently no one knows. Animal studies have discovered many beneficial effects of CBD but only when administered at very high doses, as compared to THC.

What has become quite apparent is that no single component of the plant is entirely good or bad, therapeutic or harmful, or deserving of our complete attention. To date, all of the positive evidence supporting the use of medical marijuana in humans has come from studies of the entire plant or experimental investigations of THC. Given the very low potency of CBD within the brain it is highly unlikely that CBD alone will provide significant clinical benefit. Some small clinical trials are being initiated; until rigorous scientific studies are completed no one can claim that CBD is better than THC.

© Gary L. Wenk, Ph.D. Author of Your Brain on Food (Oxford University Press)

TED talk: youtube.com

Marijuana and Coffee are Good for the Brain: youtube.com

Gary L. Wenk, Ph.D., is a Professor of Psychology & Neuroscience & Molecular Virology, Immunology and Medical Genetics at the Ohio State University.

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