"MDMA (3,4-methylenedioxymethamphetamine) is an amphetamine analog with stimulant and hallucinogenic effects.
"MDMA acts primarily on neurons that produce and release serotonin, but it also affects dopaminergic neurons. MDMA is usually taken as a pill; effects begin 30 to 60 min after ingestion and typically last 4 to 6 h. MDMA is often used at dance clubs, concerts, and rave parties.
"Symptoms and Signs
"MDMA causes a state of excitement and disinhibition and accentuates physical sensation, empathy, and feelings of interpersonal closeness. Toxic effects are similar to those of the other amphetamines but are less common, perhaps because use is more likely to be intermittent. However, even with casual use, significant problems such as hyperthermia and centrally mediated hyponatremia may occur. The effects of intermittent, occasional use are uncertain. Rarely, fulminant hepatic failure occurs.
"Chronic, repeated use may cause problems similar to those of amphetamines, including dependence. Some users develop paranoid psychosis. Cognitive decline may also occur with repeated, frequent use."

Source

"Amphetamines," The Merck Manual for Health Care Professionals, Special Subjects: Drug Use and Dependence: Amphetamines, Merck & Co. Inc. (July 2008).
http://www.merckmanuals.com/p…