Approximately 25 years ago, marijuana became a cultural phenomenon, the symbol of one generation’s disregard for another. The marijuana found on the streets at that time, however, lacked the potency of current crops. Crossbreeding of more potent varieties, improved cultivation, and the part of the plant being used all contribute to increased levels of delta-9-tetrahydrocannabinol (THC), the major psychoactive drug found in marijuana. Some marijuana currently grown in the United States rivals the previously stronger varieties of Mexico, Jamaica, and other areas. The THC percentage of Cannabis sativa (the Indian hemp plant from which marijuana is derived) in plants grown in the United States can range from 2% to as high as 7%.24 The higher the percentage of THC, the more potent the drug. Marijuana is composed of the dried leaves and flowering tops of the cannabis plant. Hashish, which has stronger effects, is processed from the resin of the plant. The resin is either dried and pressed into cakes or sold in liquid form called hash oil. Marijuana is used more extensively than hashish in the United States.
More than 400 known chemicals constitute marijuana. More than 60 of these are cannabin aids, chemicals found only in cannabis. THC is the cannabinoid that appears most responsible for the sensations experienced by marijuana users. Cannabinoids are different from other drugs in that they are fat soluble rather than water soluble; they have a decided affinity for binding to fat in the human body. Although other drugs enter and then leave the body within relatively short periods, marijuana tends to attach to fatty organs, such as the gonads and brain, and remain. A single ingestion of THC may require up to 30 days to be eliminated from the body.
Marijuana can be eaten in baked goods, such as brownies, but the effects tend to be less predictable. Because the amount ingested is more controlled, smoking is generally a more efficient and powerful technique for achieving the desired effect. When inhaled, THC reaches the brain in as little as 14 seconds. Hashish is so concentrated that a single drop can equal the effects of an entire marijuana joint (cigarette). Cannabis products are difficult to classify but are considered hallucinogens.
Small doses or short-term use of marijuana creates sensations of euphoria and relaxation, often accompanied by hunger or sleepiness. Time seems to slow, and the senses appear heightened. Memory of recent events, physical coordination, and perceptions may be impaired. Even with small amounts of marijuana, driving ability can be affected. Physiologically, heart rate speeds up and certain blood vessels become dilated, which may create problems for individuals with any type of heart problem. Some users experience anxiety, panic, and paranoia. In rare cases or with stronger doses, individuals may suffer from a sense of depersonalization, image distortion, and hallucinations. Chronic use seems to lead to behavioral changes in some people that may be permanent. Lack of motivation or interest in activities unrelated to drug use is one result. For example, students may have difficulty remembering events that occurred when they were high. Use by teenagers leads to impaired thinking, poor reading comprehension, and reduced verbal and mathematical skills.
All the long-term effects of marijuana use have not been determined. This is partly because of the lesser potency of marijuana used previously. In addition, individuals vary greatly in their responses to the drug. Chronic users may experience psychological dependence, and increased doses are needed as tolerance develops. Very heavy users experience withdrawal symptoms of restlessness, irritability, tremors, nausea, vomiting, diarrhea, and sleep disturbances
Physically, marijuana appears more carcinogenic than tobacco. Known carcinogens occur in larger amounts in marijuana, and when marijuana is smoked, the smoke is held in the lungs. Cannabis smoke contains more tars than tobacco smoke. Marijuana use quickly affects pulmonary function adversely, and long-term use causes cellular changes in the lungs. People who have angina pectoris (chest pains associated with heart disease) may be significantly at risk because more oxygen is required when using marijuana. Marijuana binds readily to hemoglobin, reducing the amount of oxygen carried to the heart and other tissues.
Many individuals consider cannabis an aphrodisiac. Over time it actually has the opposite effect, depressing the sex drive and causing impotence. Regular male users show a decrease in sperm count and reduced motility of sperm. Proportionately, more sperm appear abnormally shaped, a phenomenon associated with lessened fertility. In women, THC blocks ovulation. Pregnant women who smoke marijuana frequently use other drugs, all of which have a detrimental effect on the fetus. Marijuana also depresses the immune system.
Therapeutic use is still being explored. At this time the most promising application seems to be as an antinausea drug for chemotherapy patients. Glaucoma patients may have access to and may use marijuana to reduce intraocular pressure (pressure within the eye).
Marijuana is an illegal drug. Many people who use marijuana eventually experiment with or use other, “harder” drugs. As with alcohol and all other drugs, the way a person will react or who will be most adversely affected cannot be predicted. People do not begin use with the intention of having a drug become the focus of their life, but some ultimately allow a drug to control them. Marijuana is a drug that has that potential.