Marijuana, also called weed, is a dry green and brown mix of flowers, stems, seed and leaves from the plant Cannabis sativa, according to the National Association of Drug Abuse (NIDA). The U.S. Department of Health and Human Services reports that weed was the most commonly used illicit drug used in 2008: 6.1 percent of adults over the age of 12 reported being users of weed. However, there are multiple bad effects associated with smoking weed.
Lung Effects
NIDA reports that numerous studies have shown that marijuana smoke has the potential to cause cancer; the smoke contains carcinogens, which are substances known to cause cancer. According to NIDA, the way people smoke weed also contributes to the cancer danger: people smoking weed often breathe very deeply, and hold the smoke in their lungs for a length of time. This way of smoking allows the carcinogens to have prolonged contact with the cells of the lungs. NIDA also adds that marijuana smoke acts as an irritant to the lung tissue, which can cause a cough and an increased production of mucus. The irritants may also prevent the lungs from clearing infectious agents, increasing the frequency of lung infections.
Brain Effects
The Centers for Disease Control and Prevention (CDC) has published the Surgeon General's warning concerning the use of marijuana, which includes the detrimental effects of weed on the brain. According to this report, smoking weed significantly impairs mental functioning, mental perception and fine motor skills. NIDA also notes that smoking weed causes difficulty thinking and problem solving, and has bad effects on learning and memory formation. The effects on learning and memory can last for days or weeks, much longer than the "high" the drug causes lasts. Smoking weed also has an association with increased mental illness, such as anxiety, depression, thoughts of suicide and schizophrenia. However, NIDA notes that it is not clear whether weed causes, or is otherwise associated with, these mental illnesses. For example, there is a possibility that weed does not cause depression, but that someone with depression may smoke weed to self-medicate. More research is required to further elucidate this association.
Heart Effects
NIDA reports that smoking weed drastically increases heart rate by 20 to 100 percent. This increase in heart rate can last up to three hours. Also, according to NIDA, one study found that smoking marijuana increased the incidence of heart attack almost fivefold. Smoking weed also may cause the heart to beat irregularly. Research has shown a definite link between heart disease and smoking marijuana. A study by S Jayanthi and colleagues from the National Institutes of Health on May 13, 2008 in the journal "Molecular Psychiatry" demonstrated the first link between smoking marijuana and heart disease. The researchers tested blood from multiple marijuana users and showed that they had high levels of a protein that is a proven risk factor for heart disease.
References
- U.S. Department of Health and Human Services, Office of Applied Studies: Results from the 2008 National Survey on Drug Use and Health: National Findings
- National Institute of Drugs Abuse (NIDA): NIDA Infofacts: Marijuana
- "Molecular Psychiatry;" Heavy Marijuana Users Show Increased Serum Apolipoprotein C-III levels: Evidence from Proteomic Analyses; S Jayanthi, S Buie, R Herning, W Better, N Wilson, C Contoreggi, J Cadet; May 13, 2008.
