Marijuana is the most popular illegal drug in the world and may be the largest cash crop in the United States, as reported by ABC news in 2006. While the short-term effects of marijuana, or cannabis, are well understood, research into long-term effects remain scant, perhaps due to political polarization on the benefits and risks of cannabis for medical purposes. Regardless, some undeniable long-term risks of smoking cannabis have come to light as well as some more controversial claims.
The Smoking Gun
The most widely accepted risks for long-term marijuana use involve the popularity of consumption by smoking. Cannabis smoke contains tar, carbon monoxide and cyanide, in levels similar to tobacco smoke, according to Paul Gahlinger, M.D., author of “Illegal Drugs.” The National Highway Traffic Safety Association warns that marijuana smoke may actually contain up to five times the level of carbon monoxide as tobacco smoke.
Risk of Pulmonary Diseases
Long-term marijuana smokers often have the same daily symptoms as tobacco smokers, including smoker’s cough, increased phlegm production and symptoms of chronic bronchitis. Heavy cannabis smokers may be at a heightened risk for other pulmonary diseases as well, including emphysema and bronchial asthma. However, clinical research has not found any connection to marijuana and the increased risk of lung cancers.
The Myth of Toking
These health risks are multiplied because of the cultural practice of “toking,” which involved holding the smoke in the lungs for as long as possible to achieve maximum intoxication. This practice actually has no effect on absorbing more of the active ingredients of marijuana, but it certainly can worsen the health of the lungs, according to Gahlinger.
Controversy of Addiction
The addictive potential of marijuana remains controversial. While the National Institute of Drug Abuse warns against physical addiction, the reported withdrawal symptoms, such as reduced appetite and sleeplessness, are quite mild compared to other illegal drugs, such as heroin and cocaine. However, it is generally accepted that a considerable percentage of users develop strong psychological addictions to marijuana, according to Gahlinger. These psychological symptoms include irritability, depression, mood problems and anxiety.
Long-Term Mental Effects
This topic of long-term cognitive impairment is also controversial. The National Institute of Drug Abuse suggests that long-term use is correlated with impaired mental health and a reduced ambition for status and “life ambition.” However, earlier claims of marijuana leading to “amotivational syndrome” have been debunked, argues Gahlinger. Indeed, a 2003 study published in the “Journal of the International Neuropsychological Society” found no evidence of cognitive decline in its analysis of 15 previously reported studies. The researchers from the University of California, San Diego School of Medicine concluded that "cannabis compounds had a good margin of safety from a neurocognitive standpoint." These seemingly different opinions actually may be tracking two different trends: long-term cannabis smoking and heavy long-term smoking. More research is needed to clarify this controversial issue.
