False Facts About Marijuana You Always Thought Were True

From "Reefer Madness" to legalization, the perception of marijuana has changed drastically over the decades. Originally seen as a harmful narcotic by many, and a much-maligned harmless relaxant by others, a combination of increased visibility in the general public's eye and scientific research has shifted the common consensus over its reputation. Nonetheless, after spending many, many years in various underground sub-cultures, as well as an illegal substance, concrete facts about marijuana are often intermingled with myths. 

With the seemingly unstoppable march toward nationwide decriminalization and legalization moving along steadily, there's still a lot of false information floating around about everyone's favorite Mary Jane, whether you pass on grass or are a seasoned smoker. Its effects on health, where it's legal and where it's not, benefits and downsides, and even its potency over time, all have been wrapped in lore and legend.

So, how much do you really know about marijuana? You may be surprised — here are some false facts about marijuana you always thought were true.

The following article includes references to addiction and substance misuse. If you or anyone you know needs help with addiction issues, help is available. Visit the Substance Abuse and Mental Health Services Administration website or contact SAMHSA's National Helpline at 1-800-662-HELP (4357).

If you smoke weed, you're running the risk of forgetting everything you know, becoming psychotic, and getting lung cancer. At least, that's what the US Drug Enforcement Administration (DEA) wanted you to believe, before being forced to remove these and other false facts from their official website in February 2017, according to Americans for Safe Access.

After a legal petition was filed by the non-profit advocacy group Americans for Safe Access, the DEA removed various misleading statements. In addition to claiming marijuana causes irreversible cognitive decline in adults, is a gateway drug, and is a primary contributor to psychosis and lung cancer, the now-removed document in question also claimed, according to the Detroit Metro Times, the "legalization of marijuana, no matter how it begins, will come at the expense of our children and public safety. It will create dependency and treatment issues, and open the door to use of other drugs, impaired health, delinquent behavior, and drugged drivers." Additionally, the claim that "marijuana causes tumors in various parts of the body" was also removed.

The sticky idea that trying Mary Jane once is the first step down a long and dark path of drug misuse was perpetuated long before the days of D.A.R.E. counselors showing up to lecture your fifth-grade class. Sure, it makes sense on a very basic level — someone smokes weed, likes it, and decides they want to try harder drugs. And yes, there is a definitive correlation between smoking marijuana and using other drugs. But, as Maia Szalavitz points out in "Time," correlation is not causation. For example, Szalavitz states: "... a person who smokes marijuana is more than 104 times more likely to use cocaine than a person who never tries pot." But does that actually mean marijuana is a gateway to cocaine? By that reasoning, Szalavitz posits, riding a bike must be a gateway to joining the Hell's Angels, or childhood lullabies must be a gateway to being a Grateful Dead fan. We don't have evidence of causation.

In a Congress-commissioned report, the Institute of Medicine of the National Academy of Sciences concluded: "There is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs." 

It is a common misconception that driving under the influence of marijuana is just as bad as driving under the influence of alcohol. As science and experience shows, that's simply not the case.

Though smoking marijuana does impair psychomotor skills, the impairment is not "severe or long-lasting." According to a review of the scientific evidence by NORML, drivers who've indulged in the devil's lettuce tend to be more self-aware of their impairment — and probably the cops — and therefore tend to drive more slowly, though often taking longer to respond properly to emergency situations. (Quick thinking has never been the stoner's strong suit.)

Studies indicate that high drivers focus their attention on situations that may require a response, resulting in slower and more careful — though not necessarily safer — driving, while drunk drivers exhibit riskier behaviors in proportion to their level of intoxication, such as blowing through stop signs or speeding through town. There's a reason nearly 10,000 automotive deaths are caused by alcohol each year. But please, don't misunderstand. Stoned driving is dangerous and likely illegal, even if pot is legal.

We all remember that guy in high school who smoked a lot of weed and never really ended up doing much with his life, right? You know, the one everyone in your hometown calls a "burnout." People who smoke weed must all end up like that guy.

Even if you don't believe this judgmental statement, the stereotype perpetuated by television, movies, and some of your high school buddies is that the typical stoner is a bit of a couch potato, needing to peel their atrophying muscles off the couch to walk to the kitchen and grab some munchies, which they probably don't have because they're too lazy to go to the store. And while some potheads are lazy, so are plenty of straight shooters. Likewise, plenty of weed smokers go on to become ultra-successful, just like that square classmate who never did anything cool — but runs a Fortune 500 company now.

Loads and loads of successful people have smoked pot, and we're not just talking about the obvious ones, like Wiz Khalifa and the pizza-grubbin' Ninja Turtles. Presidents, comedians, and legendary athletes like LeBron James and Michael Phelps have taken plenty of bong hits to the face, while uber-rich Michael Bloomberg enthusiastically enjoyed indulging in some dank buds. The list goes on and on.

First of all, marijuana is addictive. Coffee is also addictive, as are cigarettes. Alcohol can certainly be addictive. What is not true, however, is that marijuana is highly addictive, like crack, amphetamines, or prescription painkillers — though this is what the Drug Enforcement Agency would like you to believe.

According to Time, only 10 percent of individuals who smoke marijuana become addicted to it — if we define addiction by the "Diagnostic and Statistical Manual of Mental Disorders" model, which describes addiction as "the compulsive use of a substance despite ongoing negative consequences, which may lead to tolerance or withdrawal symptoms when the substance is stopped." Ten percent is relatively low, especially when compared to the percentage of users dependent on tobacco, heroin, cocaine, and alcohol — all of which exhibit higher rates of addiction than marijuana. 

In addition to the comparatively lower rates of addiction, the Institute of Medicine's report "Marijuana and Medicine: Assessing the Science Base" found that "marijuana dependence appears to be less severe than dependence on other drugs."

Let's keep it real — if you're regularly ripping gravity bongs and smoking more blunts than Snoop Dogg, you're probably not doing your lungs any favors.

First and foremost, the act of putting any kind of smoke in one's lungs is going to be unhealthy. The belief that heavily smoking marijuana isn't damaging your lungs, to some degree, is just plain silly. That's not to say, however, that all smoke is created equal, and many studies have concluded that tobacco is far more harmful to one's organs than weed. According to the article "Cannabis and tobacco smoke are not equally carcinogenic," published in the Harm Reduction Journal, cannabis smoke hurts lung function and may knock lung cells into a pre-cancerous state, even if it lacks the direct causal link to cancers offered by tobacco. Marijuana, while presumably not as bad as tobacco, is still bad, as the article states: "The burning of plant material in the form of cigarettes generates a large variety of compounds that possess numerous biological activities."

Furthermore, using marijuana in any form can potentially have harmful effects on one's brain, particularly because of THC — the stuff that gets you high. In the opinion of Dr. Sushrut Jangi in the Boston Globe: "Each hit of THC rewires the function of this critical cognitive system."

It's clear that marijuana has potentially harmful effects on one's body and brain. So do alcohol, cigarettes, energy drinks, and candy. Thinking any of these things is harmless is just plain stupid. It's all about moderation.

Some people believe the prohibition of marijuana protects children from its influence. Those people are wrong. Kids are smoking pot more than ever, according to The New York Times, which claimed that, in 2011, one out of every 15 high schoolers was smoking weed on a daily basis. In 2012, CBS reported that kids smoke more pot than cigarettes. 

Roughly 70 percent of teens and adolescents believe there is no great risk in smoking weed once a month, according to VICE News. Given the number of kids smoking pot, and the use of marijuana being illegal under U.S. federal law, it seems obvious that prohibition — more than ever — does little to protect underage individuals from the potentially harmful substance.

Conversely, it's possible that the legalization of marijuana decreases the rate of teens using it. After Colorado passed Amendment 64 in 2012 — effectively legalizing weed and treating it similarly to alcohol — usage by teens took a slight decline, per Scientific American. This trend seems to hold true. According to a 2019 study published in JAMA Pediatrics (via U.S. News & World Report), teen marijuana use has either held steady or decreased slightly in all states where it had been legalized as of 2017. Researchers believe that this is because legalization actually makes it harder for underage youths to obtain weed. After all, the dealer never asked for your ID!

Ever had the bright idea, while stoned in your friend's basement, of moving to the Netherlands or Portugal, just so you can smoke weed without the hassle of cops and whatnot? Well, you can — but it's not technically as legal as you think.

In the Netherlands, cannabis is not legal, despite what many people commonly believe. According to Time, the Dutch just officially turn a blind eye, having no interest in enforcing laws against shops and cafes. Growing your own plants, selling on the streets, or importing weed are all illegal offenses in the Netherlands. Though this could be changing: In February 2023, the Netherlands' Ministries of Public Health and Justice announced that it would be rolling out "Wietexperiment" – Dutch for "Weed Experiment" – which will temporarily allow the legal sale of recreational marijuana at coffee shops in two municipalities starting at the end of 2023. After the test concludes, the government will then decide if marijuana should be legalized at all Dutch coffee shops.

Portugal is another story altogether, although some incorrectly think all drugs are legal there. Drugs in Portugal are not, in fact, legal — rather, personal use is decriminalized, punished with fines instead of jail. So smoking pot isn't really going to land you in prison. Growing and selling weed, however, definitely will.

So, if you're planning on moving to Holland or Portugal to smoke some weed in freedom, go ahead. Just know that it's not entirely free, and have some extra cash saved up for that inevitable fine.

A persisting myth about marijuana use is that it universally promotes feelings of happiness and tranquility, at least temporarily changing one's outlook for the better. But this is not always the case, and, in fact, in some instances, the exact opposite is true. According to a 2020 report published by the National Institute on Drug Abuse, marijuana use can exacerbate existing disorders like schizophrenia and can cause earlier onset of symptoms in individuals genetically at risk of developing the condition.

It can also trigger a psychotic break and may increase the likelihood of self-harm and suicidal thoughts and behaviors, especially in teens and U.S. military veterans. What's worse, people suffering from mental health conditions are more likely to self-medicate with marijuana, further compounding the problem. Yet, some people find that marijuana use does improve their mental well-being, though, admittedly, there are many factors involved – like how often and how much of the drug is used.

As a 2017 report published by the University of Washington notes, marijuana use can help combat anxiety at low doses, while, at high doses, it can actually increase anxiety. This is because THC and CBD – two chemical compounds present in marijuana – stimulate a system within the brain responsible for managing fear, memory, and stress. Small alterations can therefore have outsized effects, and reactions can vary wildly between individuals. Still, a 2022 study published in Psychiatry Research found medical cannabis to be an effective treatment option for anxiety and depression.

If you or anyone you know is having suicidal thoughts, please call the National Suicide Prevention Lifeline​ by dialing 988 or by calling 1-800-273-TALK (8255)​.

While it's true that a marijuana overdose probably won't kill you, using too much can have some uncomfortable and sometimes serious side effects. According to Calgary emergency room doctor Eddy Lang, it comes down to confusion over how the word "overdose" is defined, with many assuming someone has to die or almost die from a drug for it to qualify. "We think of it in terms of opioids, where, clearly, someone who has never taken opioids, if they take an excess amount, they will always get into trouble," Lang told CBC. "It's not as cut and dry with cannabis."

Most medical professionals agree that taking too much marijuana isn't fatal. This has to do with the way marijuana affects the physical body – or, rather, doesn't. While opioids like heroin can overly relax muscles and stop the lungs and heart, and stimulants like cocaine can dangerously increase blood pressure and cause heart attacks (per Healthline), an excess of marijuana simply dials up the discomfort. Still, the side effects of a marijuana overdose – colloquially termed a "green out" – can be pretty gnarly.

Temporary adverse psychological effects – like anxiety, paranoia, panic attacks, and psychosis – are the most common symptoms of marijuana overuse. As Healthline notes, other uncomfortable reactions like dizziness, dry mouth, increased heart rate, and hallucinations can also occur. By far the worse, though, is "cannabinoid hyperemesis syndrome," a condition that, per Cedars Sinai, causes long-term marijuana users to vomit regularly for days on end.

There's a widespread cultural assumption that marijuana always makes people calm, happy, and maybe a little cerebral or paranoid. But, as researchers are discovering, it's just not that simple. According to Healthline, marijuana plants contain many different chemical compounds, and they all have different effects on the mind and body. What's more, each plant produces varying amounts of these compounds based on genetics and propagation techniques, which means that marijuana's potential range of effects is diverse.

Historically, growers attempted to make sense of these variable highs by classifying plants as different species – primarily Cannabis indica, Cannabis sativa, and their hybrids. Modern researchers now prefer the term "chemovars," as examining the exact chemical cocktail present in each plant is the only reliable way to predict the sort of high it will provide. All marijuana plants contain dozens of cannabinoids, with the psychoactive tetrahydrocannabinol (THC) being the most well-known of these. Cannabidiol (CBD) is another, prized for its pain-killing properties. 

Cannabis plants also contain many terpenes, which can have mood-altering effects similar to essential oils, or, in the case of myrcene, sedatives. The different chemicals may also work together, creating endless combinations and effects. "Numerous basic science and even clinical trial data support the concept of herbal synergy in Cannabis beyond the effects of single components," neurologist Ethan Russo said in a 2016 interview published in Cannabis and Cannabinoid Research. "We are only seeing the very beginnings of the therapeutic potential of this plant!"

Marijuana has gained a reputation, particularly among artists and musicians, for expanding the mind and increasing creativity. Even tech guru Steve Jobs endorsed this idea! Unfortunately, it appears to be untrue – at least in the direct sense. A 2023 study published in the Journal of Applied Psychology (via Harvard Business Review) presented participants – high and sober – with several creative tasks. Researchers found that, while using marijuana did not directly increase the participants' abilities to come up with ideas, it didn't actively impair creativity, either.

It also imparted a potential benefit. The participants who used marijuana felt happier, more relaxed, and less self-critical, which meant they viewed their work – and the work of their peers – as more creative than it actually was. Just like the guy at the party who claims he plays the guitar super well when he's high but can't seem to play a note sober, the study participants tended to overestimate their abilities when using marijuana.

As Lewis Nelson – chair of medical toxicology at Rutgers New Jersey Medical School – told MIC, marijuana's impact on creativity depends on both the individual and the dosage. A naturally creative person, for example, won't feel noticeably inspired after using marijuana, but a non-creative person might find it beneficial. The amount taken also matters, with a little bit going a long way. "I can assure you that people who get a very high dose of THC won't be creative," Nelson explained. "They'll be very sleepy and very paranoid."

Many believe that the weed from "back in the day" was much stronger than the marijuana of the modern age. Nothing could be farther from the truth. After decades of intentionally breeding cannabis plants to produce stronger and better highs, all the stoner horticulturists with grow lights in their closets can finally rejoice: they have succeeded.

According to a 2018 study published in Missouri Medicine, the THC content of marijuana – that is, its most powerful psychoactive component – has increased from less than 2% in the 1960s, to around 4% in the 1990s, all the way up to a shocking 28% in 2017. This means that it is about 14 times more potent than it was when first popularized in the '60s. The saying "This ain't your granddaddy's weed" is absolutely correct! But this isn't necessarily a good thing. For one, higher THC content makes marijuana more addictive, particularly for adolescents. 

And, per Live Science, because users develop tolerances, they will consistently seek more potent marijuana to achieve the desired effects, driving levels even higher. Why is that bad? Because, as Staci Gruber – director of McLean Hospital's Marijuana Investigations for Neuroscientific Discovery program – explained to NPR, most of the negative side effects associated with marijuana stem from THC. This means that bad reactions will happen more frequently – and will be even worse. That's right, the less fun aspects of cannabis use – like paranoia, psychosis, and anxiety – will increase. Maybe Grandaddy's weed wasn't so bad after all.

While mostly known for its mind-altering effects, marijuana impacts the entire body in many ways, both good and bad. As Medical News Today notes, it can provide relief from glaucoma, stimulate appetite, relieve nausea, and reduce pain and inflammation – all things that make it useful in medical applications, especially for cancer patients undergoing chemotherapy. But marijuana also expands blood vessels, increases the heart rate, irritates bronchial passages and lungs, causes digestive upset, and suppresses the immune system. In addition, it can disrupt brain development in teens, affect tumor growth, and may cause fetal development issues during pregnancy. 

But that's not all. According to a 2022 study published in Cell (via Stanford Medicine), marijuana use also directly increases the risk of heart disease, which can lead to strokes and heart attacks. What's worse, the study also found that THC, a compound found in increasing amounts in modern marijuana, caused human blood vessel lining inflammation and contributed to atherosclerosis – that is, hardening of the arteries (per Johns Hopkins Medicine) – in mice. 

"Marijuana has a significantly adverse effect on the cardiovascular system," Dr. Mark Chandy, a medical instructor who worked on the study, told Stanford Medicine. "As more states legalize marijuana use, I expect we will begin to see a rise in heart attacks and strokes in the coming years. Our studies of human cells and mice clearly outline how THC exposure initiates a damaging molecular cascade in the blood vessels. It's not a benign drug."