History and Effects of Marijuana Use

Marijuana is the name for the drug that comes from the leaves and flowers of the Indian hemp plant, Cannabis sativa. (Elizabeth Schleichert, 1996) The plant originated in central Asia and spread to several corners of the globe. All over the world, people have used the plant as a source of fiber, cloth, paper, edible seeds, oil, and medicine. It has also been used in many cultures as an intoxicant.

The intoxicating part of the plant lies mostly in its strong-smelling, sticky, resin. This is given off by the hemp flowers, especially the flowers on the female plant. The most powerful psychoactive compounds found in the flower is called delta-9 tetrahydrocannabinol, more commonly known as delta-9 THC or just THC. THC is the chemical in the flower of the plant that is the key chemical to produce a "high."

Marijuana affects different people in different ways. It usually causes the heart rate to accelerate. This can cause panic in first-time users. (Jack Mendelson, M.D., and Nancy Mello, Ph.D. 1985) The first-time user may think that they are having a heart attack. Because of the effect of accelerated heart rate, marijuana can be very dangerous if the user has a preexisting heart problem or high blood pressure. Marijuana dries the mouth. It also dries and reddens the whites of the eyes. The eyes become red because the marijuana causes the blood vessels of the eyes to dilate or widen. This causes more blood to flow through the vessels. As other blood vessels expand, the body's blood pressure drops. This low blood pressure can cause some people to experience dizziness.