Taking small amounts of the club drug ecstasy can harm the brain, even after just one use, brain scans show.

Researchers from the Netherlands looked for subtle brain cell damage in first time users of ecstasy — an illegal drug that acts as a stimulant and psychedelic.

"We found a decrease in blood circulation in some areas of the brain in young adults who just started to use ecstasy," said Dr. Maartje de Win of the University of Amsterdam. The results of the new study were presented Monday at the annual meeting of the Radiological Society of North America in Chicago.

"In addition, we found a relative decrease in verbal memory performance in ecstasy users compared to non-users."

De Win's team used brain imaging techniques to study 59 young adults who used ecstasy for the first time, and 59 non-users. People who took the drug used six tablets on average.

After 18 months, those who took low doses of ecstasy showed no severe damage to neurons or mood.

Unknown if effects permanent

But there was evidence of changes in the structure of brain cells as well as decreased blood flow to certain regions of the brain. Users of ecstasy, also called MDMA (methylenedioxymethamphetamine) had trouble performing some memory tests.

Heavy use of ecstasy and long-term use are known to damage neurons and cause depression, anxiety, confusion, trouble sleeping and memory problems, but until now, researchers hadn't examined the side-effects of low doses in first-time users.

"We do not know if these effects are transient or permanent," de Win said. "Therefore, we cannot conclude that ecstasy, even in small doses, is safe for the brain, and people should be informed of this risk."

Small doses of ecstasy may be prescribed for people who need psychotherapy, but the results suggest the practice should be discouraged, the researchers concluded.