"Systematic review: Efficacy and safety of medical marijuana in selected neurologic disorders"

Marijuana contains approximately 60 pharmaco- logically active compounds (“cannabinoids”).D-9-Tetrahydrocannabinol (THC) was isolated in 1964 and the nonpsychoactive cannabidiol (CBD) in 1963; the ratio in botanical and phar- maceutical preparations determines therapeutic vs psychoactive effects, with the latter emerging when THC is higher in concentration...