Effects of Marijuana
The effects of marijuana experienced by users are wide ranging. These effects of marijuana resemble those of stimulants such as amphetamines, hallucinogens such as LSD, and depressants such as alcohol. As a result, marijuana cannot be placed in any one class of drugs.
The effects of marijuana are created by THC (delta-9 tetrahydrocannabinol). The THC in marijuana acts on "cannabinoid" receptors which are found on neurons in many places in the brain. These brain areas are involved in memory (the hippocampus), concentration (cerebral cortex), perception (sensory portions of the cerebral cortex), and movement (the cerebellum, substantia nigra, globus pallidus). When THC activates cannabinoid receptors, the normal functioning of these brain areas change due to the effects of marijuana. The effects of marijuana start as soon as 1-10 minutes after it is taken and can last for 3-4 hours or longer.
Scientists have known for a long time that THC interacted with cannabinoid receptors in the brain, but did not know why the brain would have such receptors. They thought that the brain must make some kind of substance that naturally acted on these receptors. In 1992, they found the answer...anandamide. Anandamide is the brain's own THC (just like "endorphin" is the brain's own morphine). Still, scientists are not sure what the function of anandamide is in the normal brain.
The most common way to use the drug is by smoking it in a marijuana cigarette. The experienced smoker of marijuana is usually aware of the effects of marijuana after two or three inhalations. As smoking continues, the effects of marijuana increase, reaching a peak about twenty minutes after the user stops smoking. Most effects of marijuana usually disappear after three hours. At that point, concentrations of THC in the body's plasma are low. When a user eats marijuana, peak effects may be delayed for three to four hours but may then last for six to eight hours.
In the early stage of the marijuana high, the user may feel euphoria (intense well-being), uncontrollable laughter, alteration of one's sense of time, sharpened vision, and depersonalization (a sense that one is detached from one's environment, and is watching one- self from a distance). Because the effects of marijuana stimulate the appetite, users often feel hungry and they report that food tastes especially satisfying or enjoyable. Later, the user becomes relaxed and experiences a dreamlike state. The effects of marijuana make thinking or concentrating difficult. However, by force of will the person can concentrate to some extent.
Two effects of marijuana intoxication are increased pulse rate and reddening of the whites of the eyes. Blood pressure may fall, especially when the user is in an upright position. The user may also feel a decrease in nausea, muscle weakness, tremors, unsteadiness, and increased reflexes (such as the knee jerk). At high doses, the effects of marijuana can impair performance of almost any task. Heavy long-term users can develop tolerance to some of the effects of marijuana. A mild withdrawal syndrome has been noted following very high doses.