MDMA users may encounter problems similar to those experienced by amphetamine and cocaine users, including addiction. In addition to its rewarding effects, MDMA’s psychological effects can include confusion, depression, sleep problems, anxiety, and paranoia during, and sometimes weeks after, taking the drug. Physical effects can include muscle tension, involuntary teeth-clenching, nausea, blurred vision, faintness, and chills or sweating.
Increases in heart rate and blood pressure are a special risk for people with circulatory or heart disease. MDMA-related fatalities at raves have been reported. The stimulant effects of the drug, which enable the user to dance for extended periods, combined with the hot, crowded conditions usually found at raves can lead to dehydration, hyperthermia, and heart or kidney failure. MDMA use damages brain serotonin neurons. Serotonin is thought to play a role in regulating mood, memory, sleep, and appetite. Recent research indicates heavy MDMA use causes persistent memory problems in humans.