Marijuana is the most commonly used illicit drug in the United States. Marijuana is addictive. While not everyone who uses marijuana becomes addicted, when a user begins to seek out and take the drug compulsively, that person is said to be dependent on the drug or addicted to it. In 2002, over 280,000 people entering drug treatment programs reported marijuana as their primary drug of abuse, showing they needed help to stop using. According to one study, marijuana use by teenagers who have prior serious antisocial problems can quickly lead to dependence on the drug. That study also found that, for troubled teenagers using tobacco, alcohol, and marijuana, progression from their first use of marijuana to regular use was about as rapid as their progression to regular tobacco use, and more rapid than the progression to regular use of alcohol.
In 2003, over 14 million Americans age 12 and older used marijuana at least once in the month prior to being surveyed, and 12.2 percent of past year marijuana users used marijuana on 300 or more days in the past 12 months. This translates into 3.1 million people using marijuana on a daily or almost daily basis over a 12-month period. In 2003, marijuana was the third most commonly abused drug mentioned in drug-related hospital emergency department visits in the United States.
A dry, shredded green/brown mix of flowers, stems, seeds, and leaves of the hemp plant, cannabis sativa. It usually is smoked as a cigarette or in a pipe. It also is smoked in blunts, which are cigars that have been emptied of tobacco and refilled with marijuana, often in combination with another drug. Use also might include mixing marijuana in food or brewing it as a tea. As a more concentrated, resinous form it is called hashish and, as a sticky black liquid and hash oil. Marijuana smoke has a pungent and distinctive, usually sweet-and-sour odor. There are countless street terms for marijuana including pot, herb, weed, grass, widow, ganja, and hash. The main active chemical in marijuana is THC, tetrahydrocannabinol. The membranes of certain nerve cells in the brain contain protein receptors that bind to THC. Once securely in place, THC kicks off a series of cellular reactions that ultimately lead to the high that users experience when they smoke marijuana. Long-term marijuana use leads to an addiction. They end up using the drug compulsively even though it interferes with family, school, work, and recreational activities. Drug craving and withdrawal symptoms can make it hard for long-term marijuana smokers to stop using the drug.
The short-term effects of marijuana addiction can include problems with memory and learning; distorted perception; difficulty in thinking and problem solving; loss of coordination; and increased heart rate. Research findings for long-term marijuana use indicate some changes in the brain similar to those seen after long-term use of other major drugs of abuse. One study has indicated that a user?s risk of heart attack more than quadruples in the first hour after smoking marijuana. The researchers suggest that such an effect might occur from marijuana?s effects on blood pressure and heart rate and reduced oxygen-carrying capacity of the blood. Smoking marijuana increases the likelihood of developing cancer of the head or neck, and the more marijuana smoked the greater the increase. A study comparing 173 cancer patients and 176 healthy individuals produced strong evidence that marijuana smoking doubled or tripled the risk of these cancers. Marijuana use also has the potential to promote cancer of the lungs and other parts of the respiratory tract because it contains irritants and carcinogens. In fact, 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 ultimately 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.
Depression, anxiety, and personality disturbances have been associated with marijuana addiction. Research clearly demonstrates that marijuana has potential to cause problems in daily life or make a person?s existing problems worse. 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. Moreover, research has shown that marijuana?s adverse impact on memory and learning can last for days or weeks after the acute effects of the drug wear off. Students who smoke marijuana get lower grades and are less likely to graduate from high school, compared with their non-smoking peers. A study of 129 college students found that, for heavy users of marijuana (those who smoked the drug at least 27 of the preceding 30 days), critical skills related to attention, memory, and learning were significantly impaired even after they had not used the drug for at least 24 hours. The heavy marijuana users in the study had more trouble sustaining and shifting their attention and in registering, organizing, and using information than did the study participants who had used marijuana no more than 3 of the previous 30 days. As a result, someone who has a marijuana addiction may be functioning at a reduced intellectual level all of the time. More recently, the same researchers showed that the ability of a group of long-term heavy marijuana users to recall words from a list remained impaired for a week after quitting, but returned to normal within 4 weeks. 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, spending work time on personal matters, and shirking tasks that adversely affect productivity and morale. In another study, marijuana users reported that use of the drug impaired several important measures of life achievement including cognitive abilities, career status, social life, and physical and mental health.
Some frequent, long-term marijuana users show signs of a lack of motivation (a motivational syndrome). Their problems include not caring about what happens in their lives, no desire to work regularly, fatigue, and a lack of concern about how they look. As a result of these symptoms, some users tend to perform poorly in school or at work. Scientists are still studying these problems.