Marijuana Abuse and Health Effects

Marijuana abuse and the effects on health

Marijuana abuse has been shown to increase users\ difficulty in trying to quit smoking tobacco. This was reported in a study comparing smoking cessation in adults who smoked both marijuana and tobacco with those who smoked only tobacco. The relationship between marijuana abuse and continued smoking was particularly strong in those who smoked marijuana daily at the time of the initial interview, 13 years prior to the followup interview.

A study of 450 individuals found that people who smoke marijuana frequently but do not smoke tobacco have more health problems and miss more days of work than nonsmokers do. Many of the extra sick days used by the marijuana smokers in the study were for respiratory illnesses.

Even infrequent marijuana abuse 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 illnesses, a heightened risk of lung infections, and a greater tendency toward obstructed airways.

Cancer of the respiratory tract and lungs may also be promoted by marijuana smoke. A study comparing 173 cancer patients and 176 healthy individuals produced strong evidence that smoking marijuana increases the likelihood of developing cancer of the head or neck, and that the more marijuana smoked, the greater the increase. A statistical analysis of the data suggested that marijuana abuse doubled or tripled the risk of these cancers.

Marijuana abuse 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 percent 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. These facts suggest that, puff for puff, smoking marijuana may increase the risk of cancer more than smoking tobacco does.

Some adverse health effects caused by marijuana abuse may occur because THC impairs the immune system\'s ability to fight off infectious diseases and cancer. One study has indicated that a person\'s risk of heart attack during the first hour after smoking marijuana is four times his or her usual risk. The researchers suggest that a heart attack might occur, in part, because marijuana raises blood pressure and heart rate and reduces the oxygen-carrying capacity of blood.

Information Released by the National Institute on Drug Abuse

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