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GENERAL CONSIDERATIONS
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This chapter reviews the problems arising from the use and abuse of cannabis and related compounds. Cannabis refers to the herbal product prepared from cannabis plants, of which there are three species: Cannabis indica, Cannabis sativa, and Cannabis ruderalis. The principal constituents of cannabis are called cannabinoids. However, in addition to cannabinoids, cannabis contains several terpenoids and flavonoids. The principal psychoactive constituent of cannabis is delta-9-tetrahydrocannabinol (THC), which is present in the hair-like glandular trichomes located around the buds of the plants (Russo, 2007). There is increasing recognition that other cannabinoids present in cannabis, such as cannabidiol (CBD), and complex interactions between the constituents of cannabis contribute to the overall effects (Potter et al, 2008). Cannabis or marijuana is referred to by a number of names including weed, pot, grass, ganja, and hash, some of which represent distinct forms of cannabis preparations. Cannabis is derived from the flowering tops and leaves of the cannabis plant. The THC content of cannabis varies according to the part of the plant: seeds > stems > leaves > flowers > bracts (Potter et al, 2008). The preparation from the buds and leaves of the pollinated female plants that have been grown outdoors is known as marijuana, whereas the preparation from the buds of female unfertilized plants is called sinsemilla (without seed). This form of cannabis is also known as skunk because of its pungent odor and because it contains higher levels of THC than most other forms. The resin secreted from the glandular trichomes is compressed to form hashish or subjected to solvent extraction to produce hash oil.
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In addition to these plant-based cannabinoids or phytocannabinoids, a number of synthetic cannabinoids have been developed. The development of synthetic cannabinoids arose from scientific interest in the endogenous cannabinoid system. However, the synthetic cannabinoids eventually started to be used by individuals for recreational purposes and became recognized substances of abuse in Europe in the early 2000s. Around 2009, synthetic cannabinoids started to appear in the United States under the name Spice and K2 (Spaderna et al, 2013). These substances were marketed as potpourri and incense and labeled "not for human consumption" in order to circumvent regulatory restrictions. The chemical composition of the early synthetic cannabinoids included JWH-018, JWH-073, JWH-200, CP 47-497, and CP 47-497C8 homologue. In early 2011, the U.S. Drug Enforcement Agency (DEA) classified these substances as schedule I substances to prevent their continued marketing. Several other synthetic cannabinoids have been developed and are found in products that are purchased for "herbal highs" (Zuba & Byrska, 2013) (Table 53–1).
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