The element within the cannabis plant that gives users a psychoactive high is tetrahydrocannabinol, more commonly abbreviated to THC. It's responsible for the euphoric, mind altering high that cannabis is notorious for, and it achieves this by binding onto CB1 (cannabinoid 1) receptors in the the brain, changing brain functions.
Commercial CBD in the UK contains less than 0.2% THC, and CBD does not bind onto CB1 receptors in the brain, meaning that CBD has no psychoactive high as what one would normally expect from consuming cannabis containing a significant volume of THC.
However, CBD has shown that it can be used to treat mental illness as well as physical ailments, inducing a therapeutic effect without a mind altering high. Some users have reported feeling more focused and energetic after using certain CBD supplements- which is the exact opposite effect THC has!
