Some drug users have said they prefer molly over other illicit drugs because of the limited negative side effects they've experienced.
"Honestly, if I were to pick a drug out of anything else to do, I would pick molly," Evan said. "Molly has a lot to do with loud music and seeing lights -- getting excited about seeing something that's already cool and making it cooler."
There are no withdrawal symptoms associated with MDMA, and because prolonged use eventually begins to diminish users' highs, the risk of physical addiction is low, said Prentiss, the Passages rehab CEO. MDMA addictions make up less than 5 percent of the company's clientele, he said.
And hospital visits spurred by MDMA use appear to be few and far between. Less than 4 percent of emergency room visits in 2009 were because of MDMA, according to the Drug Abuse Warning Network, which is part of the Substance Abuse and Mental Health Services Administration.
In fact, with its mood-enhancing properties, MDMA is even being studied as a possible treatment for post-traumatic stress disorder.
But the Drug Abuse Warning Network's study also found that from 2004 to 2009, there was a 123 percent increase in the number of emergency room visits involving MDMA taken alone or in combination with pharmaceuticals, alcohol or both.
Theodore Bania, a medical toxicologist and emergency medicine physician at St. Luke's-Roosevelt Hospital in New York, said although many of the people who take molly don't end up in the emergency room, some users experience side effects that land them in the hospital.
MDMA, even in its pure form, can produce elevated heart rates and distortion of thought processes, causing users not to realize their rising body temperature or fading stamina as they continue to party. Combining MDMA with alcohol or other drugs can also be the cause of its more serious side effects.
Bania frequently sees patients who have complications from MDMA, ranging from dehydration and exhaustion to more severe side effects such as hyperthermia, seizures, electrolyte abnormalities, cardiac episodes and comas.
MDMA also depletes the body of some of its neurotransmitters, which can lead to a decreased mood about a day or two after using the drug. Prentiss said he has even seen the drug lead to long-term depression.
Users who haven't had exposure to molly's serious negative side effects sometimes think of it as a "safer" drug. But Hart, the Columbia associate professor, said claims that any drug is safe are ridiculous.
"A lot has to do with the doses people take," Hart said. "As you increase the dose over an extended period of time, you can expect to see some negative effects. That's a general rule the public really needs to understand."
Hart said he believes accurate education, not law enforcement, is key to minimizing the risks of illicit drugs such as molly. Because so many young people have already tried molly, he said experts need to make sure they are being realistic about the dangers of its use.
"What we've done and what we consistently do is we include people that exaggerate the harms," Hart said. "Kids are not listening because they've already had the experience. ... They (think they) should reject everything we're saying because we're not being accurate, and they know it."
'A softening against drugs'
Molly's rise in popularity can, in part, be attributed to the current culture, said Tammy Anderson, a professor of sociology at the University of Delaware who has studied the use of drugs, including MDMA, in nightclubs. "We're at a place here historically that people don't think marijuana is a drug anymore."
Although marijuana, like molly, remains on the DEA's list of Schedule 1 controlled substances, it's a drug that many citizens think of not only as minor but as one that should be legal. And 17 states have legalized it for medical use.
There is now greater permissiveness and lax attitudes toward drugs such as marijuana, so people move on to other substances, such as molly, and give themselves permission to use them, Anderson said.
"We are moving into a post-war on drugs era. We're seeing a softening of drug laws and a softening against drugs, especially among young people."
For now, the DEA is more focused on fighting the abuse of prescription medications such as Oxycontin and Valium. But as admirers plaster posters at concerts asking, "Have you seen molly?" officials can only hope she stays missing.