The psychoactive components of cannabis are the cannabinoids, including delta-(9)-tetrahydrocannabinol (THC). Cannabinoid receptors CB1 and CB2 and their endogenous agonists such as anandamide have been discovered in recent years. THC and other exogenous cannabinoids can be measured in a number of tissues, including hair, saliva, blood, and, most commonly, urine [112].
