How much do you know about drugs? Even if you’re a self-proclaimed drug aficionado, you might be surprised to find that some common beliefs about drugs are more mythical than a sober person at Burning Man. Here at The Fix, we decided to countdown 10 of the top drug-related myths still in circulation today.

A lot of these myths have to do with the overblown perception of drugs and their effects and relative levels of danger. The fact that drugs are in some ways not as bad as we think, doesn’t mean that they aren’t bad at all; it just means that we need to be realistic in our discussions of them.

Ecstasy Eats Holes in Your Brain. This myth began circa 2000, when both MTV and Oprah Winfrey aired shows erroneously making this claim. The claim was based on an incorrectly interpreted scan of an ecstasy user’s brain. In the scan, there appeared to be holes in the brain tissue, but in fact this was an illusion caused by the way a computer coded the image. The spaces that looked like holes were actually areas of decreased bloodflow. It was a striking image, and it hooked the public’s imagination. The following year, the National Institute on Drug Abuse (NIDA) alleged that ecstasy caused permanent brain damage. Ten years later, though, NIDA reversed its position completely, issuing a study concluding that, when factors like sleep deprivation and previous drug use are accounted for, ecstasy may not harm your brain at all.

Most Crackheads Are Black. This belief has become so pervasive in media and pop culture that even Dave Chappelle has a skit riffing on the stereotype of a black crackhead. Although it’s been a longstanding stereotype, it’s also a longstanding misperception. As far back as 1991, a NIDA study reported that 52% of crack users were white. Today, it is true that a higher percentage of blacks than whites use crack, but that does not mean that overall there are more black crack smokers than white crack smokers. The Substance Abuse and Mental Health Services Administration (SAMHSA) found that in 2012, 62% of adults who had smoked crack in the past year were white, while 27.9% were black. Furthermore, some data indicates that whites have an overall higher rate of drug use than blacks. Despite these trends, blacks make up a larger percentage of state prison inmates serving time for drug crimes.

Crack Causes Crack Babies. On the surface, this myth sounds somewhat reasonable. After all, crack is whack, right? The thing is, whack as it is, crack doesn’t actually cause the level of fetal damage that was initially believed. Manyearly studies that found birth defects and developmental problems actually failed to account for the effects of poverty and insufficient prenatal care. To be clear, though, smoking crack during pregnancy is not good for the fetus. (Perhaps, that should not need to be stated.) It’s just not quite as bad as it initially appeared. When comparing the babies of crack smokers to those of non-crack smokers, Barry Lester, the Brown University professor who directed the Maternal Lifestyle Study, told The New York Times, “Are there differences? Yes. Are they reliable and persistent? Yes. Are they big? No.” In fact, some expertsnow estimate that the effects of smoking crack during pregnancy are less pronounced than the effects of drinking alcohol.

Everyone Who Tries Heroin Gets Addicted. Heroin is certainly bad news, but if you try it, you will not actually wake up as a full-blown junkie tomorrow morning. In fact, only 23% of individuals who try heroin go on to become dependent on it. Although that is still a fairly high number, it might seem kind of surprising in light of how heroin is perceived. By comparison, 32% of those who try tobacco go on to become dependent.

Prison Keeps People Sober. Readers of Fix contributor Seth Ferranti already know this is not true, as do viewers of Orange is the New Black or Oz. To be sure, TV is not always accurate, but it is in this case. Putting an addict in prison is no guarantee that they will stay sober. Some drugs come in from visits, some come from guards, and some come when inmates return from work release or a furlough with drugs (or, in one extreme case, drug-soaked underwear). In recent years, there have even been some news stories about enterprising individuals attempting to smuggle in drugs using drones.

Marijuana is a Gateway Drug. On some level, this seems reasonable because many people who become drug addicts began by smoking pot. In fact, someone who smokes pot is 104 times more likely to try cocaine, so there’s a high correlation between pot smoking and hard drug use—but correlation is not the same as causation. As Hal Arkowitz and Scott Lilienfeld wrote in Scientific American, “Many studies have found that most people who used other illicit drugs had, in fact, used marijuana first. Although results such as these are consistent with the gateway hypothesis, they do not prove that using marijuana causes the use of other drugs.”

The War on Drugs Has Worked. Again, informed readers know this is not true, but the myth continues to be perpetuated. In a 2010 study, SAMHSA reported that 22.6 million Americans—8.9% of the population—used illicit drugs. Clearly, the War on Drugs has not solved addiction. It has, however, cost an awful lot of money. Since Nixon officially declared war on drugs in 1971, we’ve spent $1 trillion on an offensive that has given the U.S. the world’s largest prison population. Although some claim that there would be more drug abuse were it not for the War on Drugs, it doesn’t seem to have made much of a dent in addiction; The Wire reported that the overall drug addiction rate has remained fairly constant around 1.3% since the 1970s.

Heroin is More Dangerous Than Alcohol. While it is difficult to offer adefinitive comparison between such different substances, some—including former British drug czar David Nutt—have tried. In 2010, Nutt created a rating system and ranked 20 drugs based on the 16 different types of harm they might cause. Alcohol was ranked the highest in a number of categories, including accidents and suicide, related disease, addiction, injury, family adversities, economic cost, and community. Overall, alcohol had the highest score—indicating the highest level of danger—with a 72, while heroin lagged behind in second place with a 55.

Crack Makes You Skinny. Okay, so this one is kind of true—but it’s just not as true as you might think. Although crack is an appetite suppressant, it is not a strong one. Other drugs, like amphetamines, both have a stronger appetite suppressant effect and have a longer half-life. That being said, many crack smokers experience some level of weight loss—it’s even considered one of the symptoms of crack cocaine addiction. However, that weight loss could be caused by other factors, like a lack of concern about nutrition and an interest in spending all available funds on drugs instead of food.

Heroin Overdoses Are Common. The surge in heroin-related deaths over the past couple years has resulted in increased discussion of heroin overdoses. As it turns out, though, not all overdoses are really overdoses. In a 1998 paper,Stanton Peele—author of Love and Addiction—wrote, “Heroin overdose is almost nonexistent. Rather, heroin users who concurrently take tranquilizers, alcohol, and cocaine are those at risk for sudden death.” Likewise, in a 2014 article in The Daily Beast, Dr. Anand Veeravagu and Dr. Robert Lober explained how regular users can appear to overdose: “In many cases, what causes a daily, well-tolerated occurrence to suddenly result in an unexpected death is the mixture of substances, such as alcohol or sedatives.” Of course, that’s not to say that heroin isn’t dangerous; it’s just that the true causes of heroin-related death are not always reported or understood accurately.

Keri Blakinger is a writer and prison-reform activist living in upstate New York. A staff writer for The Ithaca Times, she has also been published in The Washington Post and Quartz.