View Slideshow Ecstasy could give users serious jitters, a new study suggests. But critics say: Remain calm.
The study, the results of which were published in Friday's issue of the journal Science, says ecstasy use could cause the symptoms of Parkinson's.
But some researchers say that the study's publisher – George Ricaurte, a professor of neurology at the Johns Hopkins University School of Medicine and long-time ecstasy foe – is misleading in his interpretation of the results.
Ricaurte shows that in monkeys and baboons ecstasy caused damage to the nerves that transmit dopamine.
Dopamine is a neurotransmitter that controls movement, emotional response, and the ability to experience pleasure and pain. In Parkinson's disease, the neurons that produce it are destroyed (a phenomenon known as neurotoxicity).
But critics of the study say that Ricaurte goes too far in stating that use of the drug could cause "Parkinsonism."
"His flaw is that he uses too high a dose and uses injection (instead of oral administration)," said Dr. Juan Sanchez-Ramos, a professor of neurology at the University of South Florida in Tampa.
Ricaurte calls the amount of MDMA (the chemical name for ecstasy) administered to the animals "a common recreational dose regimen."
But critics say three injected doses within six hours, which is what Ricaurte and his colleagues gave some of the animals, is not common.
Ecstasy use is on the rise according to the latest surveys, but it's almost never injected.
Ricaurte was not immediately available for comment.
Ricaurte admits in his paper: "It is possible that humans are at a decreased risk for neurotoxic injury because of difference in the route of administration." But he goes on to say that neurotoxicity would probably still occur if taken orally.
Three doses injected within six hours actually killed two out of 10, or 20 percent, of the animals.
The researchers planned to give the other animals the same amount but decided to stop at two when they appeared to be very ill.
Given those numbers, critics question why more humans who use ecstasy were not getting sick.
"The sheer number of ecstasy users indicates that there would be millions of these patients presenting for treatment," said Jon Cole, a cognitive neuroscientist at the University of Liverpool, in a related article in Science.
Even in the monkeys and baboons that died, Ricaurte did not prove that MDMA killed any neurons, only that dopamine levels were lowered and peripheral nerve cells were damaged, Sanchez-Ramos said.
"He showed us very nicely that MDMA will kill an animal before it will kill a neuron," Sanchez-Ramos said.
Such cell damage does not prevent future dopamine production, he added. For example, FDA-approved drugs such as Thorazine and Haldol decrease dopamine transport, but they are not considered toxic for dopamine neurons.
Rick Doblin, president of the Multidisciplinary Association for Psychedelic Studies (MAPS) is putting together the first FDA-approved clinical trial on the potential therapeutic benefit of MDMA.
Because ecstasy creates feelings of euphoria, warmth and empathy, many therapists believe it could have therapeutic uses for people with post-traumatic stress disorder and other psychological problems.
Doblin questioned the timing of the release of the study: Congress is in the midst of considering the Reducing Americans Vulnerability to Ecstasy Act.
If made a law, the act would prohibit "leasing, renting, or using, or intentionally profiting from, any place ... for the purpose of manufacturing, storing, distributing, or using a controlled substance." Violators would be subject to a $250,000 fine.
"A scare about MDMA is just what people need to motivate senators to vote for the anti-rave act," Doblin said.
Other studies have shown that MDMA lowers levels of the neurotransmitter serotonin, which affects mood. This was the first study to implicate dopamine deficiency.
"These results ... suggest that recreational MDMA users may unwittingly be putting themselves at risk, either as young adults or later in life, for developing neuropsychiatric disorders related to brain dopamine and/or serotonin deficiency," the paper says.
In a press release from Science, Alan Leshner, the CEO of the American Academy for the Advancement of Science, commended the paper and warned young people not experiment with ecstasy.
Leshner is also the former director of the National Institute on Drug Abuse (NIDA).
"This study shows that even very occasional use can have long-lasting effects on many different brain systems," Leshner said. "It sends an important message to young people – don't experiment with your own brain."
Since this is the first and only paper implicating dopamine neurotoxicity rather than seratonin depletion, researchers say it's not conclusive, but it will likely instigate a re-examination of the effects of MDMA.
"The entire human literature ... relies on the notion the MDMA is a selective serotonergic neourotoxin," Cole said.