Recreational use of the illegal drug Ecstasy can alter your brain chemistry long-term, according to a new study.
Researchers say the so-called "rave" drug can lead to a drop in Serotonin levels that can last up to two years.
Serotonin is needed to regulate mood, appetite, sleep, learning and memory.
Doctors have known the drug causes these effects, but thought there would be recovery over time.
Nearly 16 million Americans age 12 and older have reported using Ecstasy at some point in their life.
The study appears in the Archives of General Psychiatry.