The whole “meth epidemic” that you’ve been told about? Maybe it’s not quite as bad as you thought.

When Columbia University psychologist Carl Hart took a peek at the data behind the media narrative on methamphetamine use, some of the more common assumptions – the idea that meth causes horrific physical transformations, is instantly addictive and is especially damaging to the brain – turned to have little foundation in evidence. In a new report [PDF] for the Open Society Foundations -- a group of foundations created by philanthropist George Soros -- Hart draws comparisons between the current media narrative of meth addiction and the hysteria over crack cocaine that flared up in the 1980s and 1990s.

“The scientific literature on methamphetamine is replete with unwarranted conclusions, which has provided fuel for the implementation of draconian drug policies that exacerbate problems faced by poor people,” Hart said in a statement.

While the market for meth is rising, it’s never been the most widely used drug. At its peak popularity, there were never more than a million users of the drug in the U.S., Hart writes. At that time, the U.S. was also home to 2.5 million cocaine users, 4.4 million illegal prescription opioid users, and 15 million marijuana smokers.

Popular advertisements (“Meth: Not Even Once”) also imply that the drug is instantaneously addictive, but the best available information suggests that fewer than 15 percent of everyone who’s ever tried meth become hooked, Hart writes.

But what about those “faces of meth” pictures? You might have seen some of them on billboards or fliers, with side-by-side images of clean-cut youngsters before they started using and their horrific afterimages: faces covered in scabs, marred by droopy skin and hair loss, and a “meth mouth” full of missing, discolored and cavity-ravaged teeth. But there’s little empirical evidence that meth directly causes physical deformities, Hart writes.

Dentists do report some individual cases of “meth mouth,” but there hasn’t yet been any large, controlled study that’s looked at the percentage of meth users that develop dental problems. Plus, there's the fact that methamphetamine and the ADHD drug Adderall are basically the same substance, i.e. speed. Despite the fact that Adderall is taken daily by patients, and is one of the 100 most commonly prescribed medicines in the U.S., there’s no epidemic of “Adderall mouth” cases.

“The physical changes that occurred in the dramatic depictions of individuals before and after their methamphetamine use are more likely related to poor sleep habits, poor dental hygiene, poor nutrition and dietary practices, and media sensationalism,” Hart writes.

Meth users may also be homeless or have untreated medical conditions, which are other factors that might contribute to a worsening physical appearance.

Newspaper front pages are happy to trumpet studies that find that meth damages the brain after long-term use, but Hart finds many of these experiments to be flawed. He takes a close look at one study covered by the New York Times in 2004. In that research, scientists used brain scans to compare the sizes of meth addicts’ brains with healthy non-drug users’, and concluded that meth impairs memory.

While the study found that parts of the meth users' brains were 8 to 11 percent smaller than those of the non-users, the researchers did not collect any data on the users before they started taking meth – thus making it pretty much impossible to prove meth alone was the cause of the brain differences. The non-drug users also had significantly more schooling than the drug users.

Even an 11 percent difference in brain structure sizes is probably within the norm of normal human variation, Hart says -- and yet there are all sorts of studies that will characterize any brain difference as dysfunction.

Addiction “certainly isn’t a brain disease like Parkinson’s disease or Alzheimer’s disease,” Hart writes. “In the case of these illnesses, one can look at the brains of affected individuals and make good predictions about the illness involved. We are nowhere near being able to distinguish the brain of a drug addict from that of non-drug addict.”

Efforts to curb meth abuse have already mirrored some of the widely criticized moves of the crack era, like mandatory minimum sentences, blamed for dramatically increasing America’s prison population (and for setting up a racist double standard that punished largely African-American crack users more harshly than largely white powder cocaine users).

Canada’s government passed a crime bill with mandatory minimum sentences for many drug crimes, including minor methamphetamine convictions. Other countries have gone down an even harsher road: Iran has a death penalty in place for mere possession of 30 grams of meth or more; Thailand banned all use of amphetamines, including for medical use, in 1996. In the U.S., efforts to curb meth by restricting access to the cold and flu medications that can be used to make meth may have had only limited success, studies show. When researchers looked at two major seizures of pseudoephedrine (as in Sudafed) in the mid-1990s, the meth market returned to business as usual within four to 18 months.

Meth does carry serious risks. But in Hart’s view, the key to helping addicts isn’t spreading messages about how awful meth is; harm reduction is the solution. Encouraging inexperienced users to avoid injecting meth in favor of consuming it by mouth, providing clean equipment for users, and revisiting harsh laws across the world are just a few of the steps that policymakers and advocates can take.

“It has taken nearly three decades for the public to come to a superficial understanding that the deleterious effects of crack cocaine were greatly exaggerated in mass media and government statements,” Hart says. “The monetary and human costs of our earlier misunderstandings about crack cocaine are incalculable.”

Whether or not this history will repeat itself is still up in the air.