This article replaces the “10 Most Common Side Effects of Using Marijuana” article that appeared here previously in the interests of having a more balanced and realistic portrayal of marijuana.
Commonly Disputed Side Effects of Using Marijuana
Marijuana, most commonly known as “weed” or “pot,” can be smoked, eaten, vaporized or (uncommonly) made into a tea to produce a “high” feeling. This high is caused by the primary psychoactive compound in marijuana, tetrahydrocannabinol (THC), interacting with the body’s cannabinoid receptors.
The high that marijuana induces is extremely subjective and is experienced by people differently but generally will include feelings of relaxation, mild paranoia and anxiety, alteration of visual, auditory, and olfactory senses, fatigue, and stimulation of the appetite.
And although no deaths have been directly related to smoking marijuana, it has been shown to produce some potentially negative side effects in people. Many of these side effects, although backed by scientific studies, have also been disputed and discredited by other scientific studies and reviews, making marijuana a hotly disputed topic.
Although almost all reported side effects of smoking marijuana are disputed, some common ones that can easily be observed are reddening of the eyes, dryness of the mouth and increase in heart rate. It has also been linked to a decrease in intra-ocular pressure, which is why it is sometimes prescribed for people with glaucoma (a condition that involves pressure on the eye).
Many studies have been done about marijuana’s effects in regard to bipolar disorder, depression, mood swings and schizophrenia, but no reliable conclusions have been achieved, as there are just as many studies that have drawn a correlation between marijuana use and these disorders as there are scientific studies and scientific peer reviews that say there is no correlation at all. For example, in one study, “Moderation of the Effect of Adolescent-Onset Cannabis Use on Adult Psychosis by a Functional Polymorphism in the Catechol-O-Methyltransferase Gene: Longitudinal Evidence of a Gene X Environment Interaction”published in Biological Psychiatry, researchers claimed to find a link between marijuana use and psychosis, however, a different study “Genotype effects of CHRNA7, CNR1 and COMT in schizophrenia: interactions with tobacco and cannabis use” published in The British Journal of Psychiatry has cast doubt on those findings. There are dozens of these types of studies that make conclusions one way or the other depending on how the results are interpreted, making them all relatively useless when trying to pinpoint long-term health effects of marijuana.
And although a German study allegedly found that marijuana use was a direct causal factor in some cases of schizophrenia, the fact that marijuana use has skyrocketed in most countries in the past few decades while cases of schizophrenia and psychosis have stayed the same makes that study’s conclusion seem highly doubtful.
Another study published in The British Journal of Psychiatry, “Causal association between cannabis and psychosis: examination of the evidence,” found that while marijuana generally exacerbates the onset of psychosis in people who are predisposed to having the condition, it won’t cause a condition in a healthy person.
Several studies have also been published that both claim and dispute marijuana’s negative side effects on the development of adolescent brains, long and short term memory and the capacity for learning.
In his book The Science of Marijuana, professor of pharmacology at the University of Cambridge Leslie L. Iversen says between 10 to 30 percent of regular marijuana users will develop a dependency on it but only about 9 percent will develop a serious addiction to it.
In the book, Iversen reviews decades of international laboratory and survey research on marijuana.
Compared to harder drugs like cocaine or heroin (or even the perfectly legal nicotine) marijuana has few severe withdrawal symptoms and the majority of people who use it recreationally are able to quit easily. Withdrawal symptoms might include mild anxiety, depression, nausea, insomnia and some gastrointestinal problems.
Although there has been no long-term study linking marijuana use to cancer, it certainly cannot be ruled out. (And smoking it certainly does not cure cancer like some marijuana users like to claim.)
THC is a relatively harmless drug for the human body but the problem is that to get THC into their systems, most people choose to smoke it and that’s where it can become dangerous. Scientific analyses of marijuana smoke, cited in Iversen’s book, have identified at least 6,000 of the same chemicals in marijuana smoke as are present in tobacco smoke. Smoked marijuana and smoked tobacco are chemically very similar, the main difference between them being the THC in marijuana and the nicotine in tobacco.
A potent carcinogen in tobacco smoke, benzo(α)pyrene, is present in higher amounts in marijuana smoke. And because marijuana smokers usually hold the smoke in their lungs longer than cigarette smokers, this increases the amount of tar deposited in the respiratory system.
Using vaporizers, water pipes or ingesting marijuana by eating it are ways to help avoid some of the chemical found in marijuana smoke.
But despite marijuana smoke being quite similar to tobacco smoke, several studies have been conducted and have concluded that even daily smoking of marijuana has little negative effect on the body’s respiratory system.
Dr. Donald Tashkin, who has done extensive research on marijuana smoke, has said “that essentially there is no significant relationship between marijuana exposure and impairment in lung function.” He also added that this could be due to THC’s anti-inflammatory effect.
Marijuana acts as a gateway drug
Many anti-marijuana activists like to point to the theory that marijuana acts as a gateway drug for young people, leading them to try other, harder drugs down the road. However, there has been no conclusive study to prove this theory and because of the fact that both alcohol and nicotine tend to be much more readily available and are often used in conjunction with marijuana by young people, the theory has been impossible to conclusively prove.
The effects and side effects of marijuana will likely continue to be studied, debated, hyped, lied about, proven and disproven moving forward. The only sure thing every person can agree on is that marijuana will continue to be hotly debated as laws surrounding it continue to soften.