Medical Research

CBD’s Impact on Serotonin

Written by Lydia Kariuki

What Is Serotonin?

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a neurotransmitter (brain chemical) that regulates feelings of wellbeing and happiness. However, it is a multi-faceted compound with diverse functions in the human body.

This neurotransmitter is primarily produced in the gastrointestinal tract (90%) in enterochromaffin cells where it regulates GI motility.[1] However, it is also present in the central nervous system in serotonergic neurons where it contributes to mood regulation, memory, sleep, cognition, learning, vomiting, and vasoconstriction.

While many different chemicals impact mood, when serotonin production is altered, a person is likely to experience negative emotions such as depression, anxiety, and insomnia.

How Does CBD Affect Serotonin?

A study published in Neurochemical Research in 2005 investigated the mechanism through which cannabidiol (CBD) interacts with the serotonergic system. This study was spearheaded by one of the leading researchers in medicinal cannabis, Ethan Russo, MD.[2]

According to the results of this study, CBD acts as a “modest affinity agonist” at the 5-HT1a receptor, meaning that it increases binding at the receptor in a similar way that serotonin does. In contrast, tetrahydrocannabinol (THC) did not produce this effect.[2] This mechanism makes CBD a potential therapeutic agent in combating conditions like anxiety and depression through its effect on serotonin.

Another study found that CBD exerts antidepressant effects directly through the serotonin system, as co-administration of CBD with a serotonin blocker reversed the benefits of CBD alone.[3]

Can CBD Be Used to Treat Depression?

Selective Serotonin Reuptake Inhibitors (SSRIs) work by inhibiting the reuptake or break down of serotonin from the body. In this way they allow for more serotonin to be in circulation. Common SSRIs include drugs such as Prozac®.

While additional research is needed to better understand how cannabinoids can treat depression in humans, CBD is generally safe and well tolerated, which may be a better option than medications with significant side effects.

The studies described above were conducted in animal models. Therefore, randomized clinical trials would help provide clear guidance in this area.

As always, talk to your doctor before using CBD or cannabinoids to treat any medical conditions.

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  1. Bellono NW, et al. Enterochromaffin cells are gut chemosensors that couple to sensory neural pathways. Cell. 2017;170(1):185-198.
  2. Russo EB, et al. Agonistic properties of cannabidiol at 5-HT1a receptors. Neurochem Res. 2005;30:1037-1043.
  3. Sales AJ, et al. Antidepressant-like effect induced by cannabidiol is dependent on brain serotonin levels. Prog Neuropsychopharmacol Biol Psychiatry. 2018;86:255-261.

About the author

Lydia Kariuki