A new study suggests that Ecstasy use may be associated with long-term changes in the brain. The more Ecstasy a person uses, the greater the changes.

Medical News Today reports that researchers examined brain activity in people who had previously used Ecstasy and those who had never taken the drug. Brain activity was measured using functional magnetic resonance imaging. In the journal Neuropsychopharmacology, the scientists report that people with the highest lifetime exposure to Ecstasy had increased activity in three areas of the brain associated with visual processing.

This increase in brain activation did not return to normal, even in people who had not used the drug in more than a year. The researchers say that the results suggest that using Ecstasy leads to chronic changes in the brain’s visual system. The article notes that the 2009 National Survey on Drug Use and Health found that 760,000 people ages 12 or older had used Ecstasy in the month before being surveyed.