Cannabidiol

Overview
Cannabidiol, also known as CBD, is an antipsychotic cannabinoid found in the hemp plant Cannabis sativa. It is a major constituent of the plant, representing up to 40% in its extracts.

CBD alone is not intoxicating, but it appears to affect the euphoric effect of THC (which is an isomer of cannabidiol) and add a sedative quality. Some research, however, indicates that CBD can increase alertness. It may decrease the rate of THC clearance from the body, perhaps by interfering with the metabolism of THC in the liver. CBD does not appear to affect either the CB1 or CB2 receptors.

Medically, it appears to relieve convulsion, inflammation, anxiety, and nausea, as well as inhibit cancer cell growth. Recent studies have shown cannabidiol to be as effective as atypical antipsychotics in treating schizophrenia.

Medicinal use
In April 2005, Canadian authorities approved the marketing of Sativex, a mouth spray for multiple sclerosis to alleviate pain. Sativex contains tetrahydrocannabinol together with cannabidiol. It is marketed in Canada by GW Pharmaceuticals.

Cannabidiol has also been shown to inhibit cancer cell growth, with low potency in non-cancer cells. Although the inhibitory mechanism is not yet fully understood, Ligresti et al suggest that "cannabidiol exerts its effects on these cells through a combination of mechanisms that include either direct or indirect activation of CB2 and TRPV1 receptors, and induction of oxidative stress, all contributing to induce apoptosis."