Safety, efficacy, and mechanisms of action of cannabinoids in neurological disorders.

In the past two decades, there has been an increasing interest in the therapeutic potential of cannabinoids for neurological disorders such as epilepsy, multiple sclerosis, pain, and neurodegenerative diseases. Cannabis-based treatments for pain and spasticity in patients with multiple sclerosis have been approved in some countries. Randomised controlled trials of plant-derived cannabidiol for treatment of Lennox-Gastaut syndrome and Dravet syndrome, two severe childhood-onset epilepsies, provide evidence of anti-seizure effects. However, small clinical trials of cannabinoids in other neurological disorders such as Huntington's disease, attention deficit hyperactivity disorder, and dementia, have not found any effect. Despite positive results in these two severe epilepsy syndromes, further studies are needed to determine if the anti-seizure effects of cannabidiol extend to other forms of epilepsy, to overcome pharmacokinetic challenges with oral cannabinoids, and to uncover the exact mechanisms by which cannabidiol or other exogenous and endogenous cannabinoids exert their therapeutic effects.