There could be anything in that capsule. (Flickr user Shivenis/CC).

Everyone's talking about "Molly" after 12 Wesleyan University students were hospitalized over the weekend after taking the drug. While the incident is raising alarm in some quarters over the supposed "rise" of Molly use among young people, the actual data we have on the drug doesn't paint as clear a picture -- for starters, in many cases it's difficult to determine what Molly even contains.

The drug is sold as capsules containing pure MDMA -- the active ingredient in Ecstasy pills. This alleged purity is partly responsible for the assumption among some users that Molly is safer than Ecstasy. And pure, pharmaceutical-grade MDMA is, in fact, pretty darn safe, at least under a doctor's supervision. Early trials using the drug to treat PTSD among war veterans have shown promising results.

But the problem with the Molly you buy on the street is that you don't actually know what's in that capsule. Powder in a capsule is actually easier for dealers and manufacturers to tamper with than pills. Joseph Palamar is an NYU researcher who studies the use of Ecstasy and other drugs. "One of the problems with Molly is that when something is sold as a powder it could be cut with another drug at any level of production," he said in an interview.

When someone shows up to an ER after having taken Molly, as the Wesleyan students did this weekend, there's no telling what's actually in their system. "Molly is supposed to be pure. But a lot of times it has zero MDMA in it," Palamar told me. So reporting that the Wesleyan students have "overdosed" on the drug, as many news outlets have done, is almost certainly not correct. In cases like this, people are usually getting sick not because they're taking too much MDMA, but because they're taking MDMA adulterated with any number of far more dangerous drugs.

On top of that, many kids don't even realize that Molly is as a form of Ecstasy, or that the active ingredient in both is MDMA. All this uncertainty adds a certain amount of fuzziness to survey-based measures of the drug's use.

We do know that in 2013, 4 percent of 18 to 25-year-olds say they used "Ecstasy" in the past year. This is essentially unchanged from the prior few years, but down sharply from 2002, when almost 6 percent reported using the drug. As far as drugs go, ecstasy is less popular in that age group than cocaine, and half as popular as recreational painkillers. And of course the elephants in that room -- and not included in the chart -- are tobacco, alcohol and marijuana, with past-year use rates for 21 to 25-year-olds of 50 percent, 84 percent and 29 percent, respectively.

The amount of domestic MDMA seized by the Drug Enforcement Administration has dropped sharply since 2009. While this could be due to changes in law enforcement priorities, these numbers don't quite mesh with the notion that Ecstasy is becoming more prevalent across the U.S.

Finally, while Ecstasy-related ER visits surged from 2007 to 2009, they flattened out between 2009 and 2011. Unfortunately these emergency department numbers aren't updated as frequently as other indicators, so we can't tell what hospital visits look like from 2012 onward.

Overall, the numbers taken together point a picture of a rise in use from the early to late 2000s, followed by decline and plateau in the case of the usage rates and ER visits, and a sharp drop in the total quantity seized by the DEA. So while its worth keeping an eye on these trends, fears of an epidemic are probably overblown.

That said, there's little question that popping pills and capsules of unknown purity and potency is a highly risky proposition. Policymakers concerned about dangers associated with the drug have some tools at their disposal to reduce those risks. Colleges and universities should consider enacting Good Samaritan policies that shield drug users or their friends from criminal charges if they seek help for an overdose, says NYU's Palamar. "If a student on campus is sick [from a drug], that student or his friends shouldn't have to worry about seeking help," he says. "This puts health before the criminal justice aspect."

Testing drugs for purity at music events can also be a huge help, but many promoters are wary of doing that for fear of running afoul of strict federal drug laws. Some buyers concerned about purity and safety have turned to the online black markets, where a robust system of buyer-generated product reviews -- like eBay, or Amazon -- keep sellers honest. But the federal government has been single-mindedly focused on shutting those sites down, leaving buyers little choice but to turn to the guy on the street -- and whatever he happens to be selling that day.