The investigators found that this shift in brain excitability did not return to normal in subjects who had not used Ecstasy in more than a year.
"We think this shift in cortical excitability may be chronic, long-lasting, and even permanent, which is a real worry," Cowan said, noting that the Ecstasy users in the study are young (18 to 35 years old). "The question is what will happen to their brains as they age over the next 60 years."
Cowan said that the pattern of hyper-excitability is similar to that observed in fMRI studies of individuals at risk for, or with early, Alzheimer's disease.
"I'm not saying that these people are at increased risk for dementia, but that there's a loss of brain efficiency in both recreational Ecstasy use and early Alzheimer's."
The findings suggest that brain hyper-excitability (increased activation in fMRI scans) may be a useful biomarker for Ecstasy-induced neurotoxicity, which the investigators will continue to study.
"Our goal is to be able to let people know whether or not the drug is causing long-term brain damage," Cowan said. "That's really critical because millions of people are using it."
The 2009 National Survey on Drug Use and Health estimated that 14.2 million individuals 12 years or older in the United States had used Ecstasy in their lifetime; 760,000 people had used Ecstasy in the month prior to being surveyed.
Cowan is also interested in determining the doses of Ecstasy that are toxic, and whether there are genetic vulnerabilities to toxicity. If clinical trials show that the drug has therapeutic benefits, it's critical to know the risks, he said.
|Contact: Leigh MacMillan|
Vanderbilt University Medical Center