Clinical Textbook of Addictive Disorders 3rd ed - R. Frances, S. Miller, A. Mack (Guilford, 2005) WW

160 III. SUBSTANCES OF ABUSEaffinity. This effect may be to stimulate, to inhibit, or a variety of in-betweeneffects. The natural ligand for marijuana is called anandamide, and its receptoris the anandamide receptor. Interestingly, the term “anandamide” is derivedfrom the Hindi word for bless. At present, pharmaceutical companies have synthesizedboth agonists and antagonists to the receptor. Much research has beenconducted to identify the properties of these compounds, but it is still unclearwhat function they serve in mammalian and human brains. Cannabinoid receptorshave been described in various regions of the brain, with the greatest abundancein the basal ganglia and hippocampus, areas involved with memory function.The hemp plant synthesizes at least 400 chemicals, of which more than 60are cannabinoid. Pyrolyzing the plant can create even more molecules. Very littleis known about the vast majorities of these molecules or their effects onhuman. The most psychologically and physiologically active compound isTHC. In the pyrolyzed form, it actually becomes delta-11-tetrahydrocanbonol.This molecule is believed to account for most of marijuana’s effects. There are,however, numerous compounds whose effects remain completely unknown. Forinstance, it is known that marijuana use raises the seizure threshold overall andmakes it more difficult to have a seizure (Zagnoni & Albano, 2002). THCalone decreases the seizure threshold. This property of marijuana, therefore, isnot the result of THC, but rather some other cannabinoid. The two most abundantcannabinoids are cannabinol and cannabidiol. Much research is currentlyunderway regarding the possible use of marijuana in clinical or other settings.Physiological EffectsCannabis intoxication commonly heightens the user’s sensitivity to externalstimuli, thus making colors seem brighter and smells more pungent. It also distorts,sometimes severely, the user’s sense of time. The term “temporal disintegration”(Mathew, Wilson, Humphreys, Lowe, & Weithe, 1993) has beencoined to describe this slowing of subjective time after use of marijuana. Inaddition, at least in low doses, marijuana causes mild euphoria and feelings ofrelaxation. It is also know to increase appetite. There is some controversy overwhether individuals intoxicated with cannabis pose a hazard, as they seem to beattracted to thrill-seeking behavior and are usually subdued. Some people haveargued that individuals who smoke marijuana are less likely to drive fast; however,reaction time to complex and unforeseen situations is slowed, and musclestrength and hand–eye coordination is decreased. Because it delays reactiontime, alters time perception, and for many other reasons, marijuana must beconsidered a danger to those who would operate a motor vehicle or use complexmachinery or equipment, thus putting themselves and others in danger.At higher dose levels and with chronic patterns of use, cannabis caninduce panic attacks (Deas, Gerding, & Hazy, 2000). This is especially com-