According to the National Institute on Drug Abuse, pot (marijuana) is the most commonly abused illicit drug in the United States. The active ingredient in pot is THC (delta-9-tetrahydrocannabinol). When you smoke pot, THC travels from the lungs into the bloodstream and on to the brain and bodily organs, where it can cause a number of common and potentially serious side effects.
Common Side Effects
Smoking pot can affect your brain and physical, mental and emotional health. Because of the way pot alters the brain, it may cause slowed reaction time, impaired concentration, altered time perception, impaired coordination, difficulty solving problems and organizing thoughts and problems with learning and memory. The effects on memory and learning can last for days or weeks, so someone who smokes regularly may never feel moments of mental clarity.
Other common physical and emotional side effects of pot include anxiety, sleepiness, bloodshot eyes, headache, nausea, reproductive organ changes, tremors (shaking) and increased appetite.
Heart and Lung Side Effects
Marijuana contains carcinogens, or cancer-causing chemicals. According to the National Institute on Drug Abuse, pot contains 50 to 70 percent more carcinogens than the tobacco found in cigarettes. Although more research is needed to determine whether smoking marijuana directly causes cancer, studies have shown that pot smokers are more likely to show abnormalities in the cells in their lung tissue and to have a number of respiratory problems, including a regular cough, excessive phlegm production, more frequent chest illnesses and respiratory conditions. Frequent pot smokers are also more likely to miss more days of work as a result of lung conditions.
Pot increases heart rate for up to three hours after you smoke. Findings from a study published in a 2001 issue of "Circulation" estimate that pot smokers increase their chances of having a heart attack by almost fivefold in the first hour after smoking due to its effects on heart rate and its tendency to cause heart palpitations and arrhythmias.
Dependence and Withdrawal Effects
Regular, long-term use of marijuana can lead to physical addition. Individuals with a dependence on marijuana who stop smoking will experience a range of side effects related to withdrawal including irritability, sleeplessness, decreased appetite, anxiety and drug craving. Symptoms of withdrawal typically reach their peak two to three days after stopping smoking and subside within a couple of weeks.