12/05/2011 04:04 EST | Updated 02/04/2012 05:12 EST

Ecstasy Users' Brains Show Toxic Effects


Female Ecstasy users show long-lasting signs of toxicity in their brains, an imaging study shows.

The neurotransmitter serotonin, a critical signaling molecule, has roles in regulating mood, appetite, sleep, learning and memory.

In Monday's issue of the Archives of General Psychiatry, U.S. researchers used PET scans to look at levels of certain serotonin receptors in different regions of the brain in 15 women who had used Ecstasy compared with 10 who never taken it.

The study is important, said study author Dr. Ronald Cowan, a psychiatry professor at Vanderbilt University in Nashville, because the drug is now being tested as a treatment for post-traumatic stress disorder and anxiety associated with cancer.

"Our studies suggest that if you use Ecstasy recreationally, the more you use, the more brain changes you get, Cowan said. Investigators will need to know the dose at which Ecstasy becomes toxic before it is used as a treatment, the study's authors cautioned.

In the study, they found Ecstasy use produces chronic serotonin neurotoxicity in humans.

Since previous studies suggest that the use of birth control, estrogen level and age affect serotonin receptors, the researchers took those factors were taken into consideration in the analysis. But the authors acknowledged they may not have fully accounted for those variables.

"Given the broad role that serotonin plays in human brain function, the possibility for therapeutic MDMA use, and the widespread recreational popularity of this drug, our results have critical implications for human MDMA users," the investigators concluded.

To be eligible for the study, Ecstasy users couldn't take it in the nine days before the imaging study. When hair samples were analyzed to test for drug use, one woman was excluded from the study because of a positive cocaine result.

Participants were aged 18 to 25.

The study focused on healthy women and the findings may not apply to men or those with anxiety or depression, the researchers said.

The research was funded by the U.S. National Institute on Drug Abuse, the U.S. National Institute of Mental Health, and the U.S. National Center for Research Resources.