Marijuana is the most commonly used illicit drug 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. Marijuana smoke has a pungent and distinctive, usually sweet-and-sour odor. The main active chemical in marijuana is THC. 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. When someone smokes marijuana, THC rapidly passes from the
lungs into the bloodstream, which carries the chemical to organs throughout the body, including the brain. |
The short-term effects of marijuana 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. |
Even infrequent use 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 phlegm production, more frequent acute chest illness, a heightened risk of lung infections, and a greater tendency to obstructed airways. Smoking marijuana increases the likelihood of developing cancer of the head or neck, and the more marijuana smoked the greater the increase. 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. |
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 blood. |
If someone is high on marijuana, he or she might: seem dizzy & have trouble walking; seem silly and giggly for no reason; have very red, bloodshot eyes;
and have a hard time remembering things that just happened. |
Depression, anxiety, and personality disturbances have been associated with marijuana use. Marijuana has potential to cause problems in daily life or make a person’s existing problems worse. Marijuana compromises the ability to learn and remember information. |
