Ecstasy is a stimulant like various classes of amphetamines, but the popular club drug is more likely to kill young and otherwise healthy users, Reuters reported Jan. 29.

U.K. researchers who studied ecstasy and amphetamine related deaths found that ecstasy-related deaths were more common among “victims who were young, healthy, and less likely to be known as drug users.”

Study author Fabrizio Schifano of the University of Hertfordshire said that ecstasy seemed to have a higher “intrinsic toxicity,” particularly among users ages 16-24. Schifano speculated that the deaths could be related to the fact that adolescents’ brains are still developing.

The study was published in the journal Neuropsychobiology.