Marijuana is the most commonly used illegal drug in the United States. It is made from the dried leaves and flowering tops of the Indian hemp plant Cannabis Sativa. People smoke, chew, or eat marijuana for its hallucinogenic and intoxicating effects. The flowering tops of the Cannabis plant secrete a sticky resin that contains the active ingredient of marijuana, known as Delta-9-Tetrahydrocannabinol (THC). The plant has both male and female forms. The sticky flowers of the female plant are the most potent. Hashish is a similar drug prepared from the same plant. It differs from marijuana in that it is made of only the resin from the plant, but where marijuana is made up of flowering tops and leaves.
The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). The membranes of certain nerve cells in the brain contain protein receptors that bind to THC. Once securely in place, THC initiates a series of cellular reactions that lead to the high that users experience when they smoke marijuana. There are usually phases in marijuana use there are: intoxication, initial stimulation, which includes giddiness and euphoria, followed by sedation and pleasant tranquility. Mood changes are often accompanied by altered perceptions of time and space. Thinking processes become disrupted by fragmentary ideas and memories. Other feelings include increased appetite, heightened sensory awareness, and general feelings of pleasure.
Negative effects of marijuana use can include confusion, acute panic reactions, anxiety attacks, fear, a sense of helplessness, and loss of self-control. Like alcohol intoxication, marijuana intoxication impairs judgment, comprehension, memory, speech, problem-solving ability, reaction time, and driving skills. Although marijuana is not physically addicting and no physical withdrawal symptoms occur when use is discontinued, psychological dependence develops in some 10 to 20 percent of long-term regular users. Smoking marijuana can damage the lungs, and long-term use may increase the risk of lung cancer . Even infrequent use of marijuana can cause burning and stinging of the mouth and throat, often accompanied by a heavy cough. Someone who smokes marijuana regularly may have many of the same respiratory problems that tobacco smokers do, such as daily cough and
frequent chest illness, a heightened risk of lung infections, and a greater tendency to obstructed airways. Cancer of the respiratory tract and lungs may also be promoted by marijuana smoke.
Marijuana use has the potential to promote cancer of the lungs and other parts of the respiratory tract because it contains irritants and carcinogens. Marijuana smoke contains 50 to 70 percent more carcinogenic hydrocarbons than does tobacco smoke. It also produces high levels of an enzyme that converts certain hydrocarbons into their carcinogenic form, levels that may accelerate the changes that produce malignant cells. Marijuana users usually inhale more deeply and hold their breath longer than tobacco smokers do, which increases the lungs exposure to carcinogenic smoke.Some other effects of marijuana may occur because THC impairs the immune system’s ability to fight off infectious diseases and cancer. In laboratory experiments that exposed animal and human cells to THC or other marijuana ingredients, the normal disease-preventing reactions of many of the key types of immune cells were inhibited. In other studies, mice exposed to THC or related substances were more likely than unexposed mice to develop bacterial infections and tumors
Depression, anxiety, and personality disturbances are all associated with marijuana use. Because marijuana compromises the ability to learn and remember information, the more a person uses marijuana the more he or she is likely to fall behind in accumulating intellectual, job, or social skills. Students who smoke marijuana get lower grades and are less likely to graduate from high school, compared to their non-smoking peers. Workers who smoke marijuana are more likely than their coworkers to have problems on the job. Several studies associate workers’ marijuana smoking with increased absences, tardiness, accidents, workers’ compensation claims, and job turnover. A study of municipal workers found that those who used marijuana on or off the job reported more “withdrawal behaviors” such as leaving work without permission, daydreaming, and spending work time on personal matters.
Although no medications are currently available for treating marijuana abuse, recent discoveries about the workings of the THC receptors have raised the possibility of eventually developing a medication that will block the intoxicating effects of THC. Such a medication might be used to prevent relapse to marijuana abuse by lessening or eliminating its appeal.