The deaths of two young adults and the hospitalization of four others this weekend following a massive electronic music festival in New York City — which was subsequently shut down by city officials — has reignited fears over the club drug MDMA, nicknamed “Molly,” which is the suspected cause of the deaths.
And while the drug, a purer, powdered form of Ecstasy chemically known as methylenedioxymethamphetamine, has been around for decades, it has lately surged in popularity with college students, and is being name-checked by mainstream artists ranging from Kanye West and Rick Ross to Miley Cyrus and Madonna.
According to the Drug Enforcement Administration, Molly can be taken orally in powder, tablet or capsule form. The effects, which include a sense of increased energy, euphoria and empathy, can last from three to six hours after ingestion, according to the National Institute on Drug Abuse.
It was first created as a diet drug in 1914, and in 1970s was used by doctors as an aid in psychotherapy. In the 1980s and 1990s it burst upon the club scene as a party drug.
Today, the drug is currently in clinical trials as a potential aid to treat post-traumatic stress disorder as well as anxiety in terminal cancer patients, according to DrugAbuse.gov.
But experts say Molly is becoming a popular party drug again — with reports of MDMA-related emergency room visits having doubled since 2004 — and can be dangerous to casual users for a range of reasons, with a major one being that it’s hard to detect when an overdose looms.
Dr. Meika Roberson of Mount Sinai Hospital in New York said that it’s very difficult for concert-goers who use Molly to sense whether or not they are on the brink of an overdose.
“The early signs of intoxication going over toward overdose of MDMA, of Molly, is going to be high heart rate, high respiratory rate and high blood pressure,” she said. “So if you're in a club scene, you're not feeling any of that.”
And as reports of Molly-related deaths and hospitalizations increase, celebrity musicians who have referenced the term “Molly” in their music are facing growing scrutiny.
Madonna named an album with a similar-sounding name — “M-D-N-A” — and was criticized for a question she asked the audience during a show last year in Miami, Fl.
“How many people in this crowd have seen Molly?” she asked.
And while Ecstasy itself was never very popular among the hip-hop set, Molly seems to have caught on. Kanye West has rapped about it and rapper Rick Ross reportedly even lost an endorsement after he referenced the drug in lyrics.
Most recently, the producers of the MTV Video Music Awards on Aug. 25 bleeped a part of Miley Cyrus’ single, “We Can’t Stop,” when she sang the line, “Dancing with Molly.”
Along with the two suspected Molly-related deaths this weekend in New York City, two additional deaths this summer have been linked to the drug.
A 19-year-old girl died last week in Boston of a suspected overdose following a concert. It was reportedly the college student’s first concert.
And in June, a man died and dozens more were treated for overdosing on the drug at a music festival in Washington state.
Also in Boston on Saturday three people were treated for drug overdoses at a techno-rock music festival, but it was unclear if the substances involved included MDMA, according to the Boston Herald.
The New York City Health Department told NBC News that, on average, they see about 10 MDMA-related overdose deaths per year — but a spokesman Sunday said that "two deaths, back to back, is worrisome.”
NBC News' Ron Mott, Tom Winter and Daniel Arkin contributed to this report.