The plant cannabis contains 120 different cannabinoids, but the two most abundant are cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC). THC is solely responsible for the psychological impacts of cannabis due to its ability to activate the CB1 cannabinoid receptor on neurons in the brain; thus, its use is tightly regulated in most countries. In contrast, CBD is not a controlled substance in many countries; in fact, in the European Union, no analytical controls are mandatory for CBD-based products and variability in CBD concentrations in commercialized CBD oil preparations are pronounced and prevalent.
Such availability of CBD paved the way for observations that it alleviates symptoms in those with seizure disorders, particularly in children. This led to an increasing level of interest in therapeutic potentials of CBD in particular and cannabis in general among the medical and scientific community in the past decade. As a result, clinical trials began being carried out to examine the effectiveness and safety of cannabis-based medicine in a wide range of neurological disorders. As an example, recently, CBD was proved to have significant anti-seizure effects for patients with Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS) - two rare forms of epilepsy and in 2018 was approved by the Food and Drug Administration as an add-on drug for patients with these conditions. Other cannabis-derived drugs with varying ratios of THC/CBD also demonstrated promising safety and benefits, such as anxiety-relieving, antiemetic and anti-inflammatory in studies and might one day become available to patients in the clinics.