MDMA causes excitement and disinhibition (a loosening of control over behaviors). It also 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 people are more likely to use MDMA intermittently. However, even with casual use, significant problems such as hyperthermia and hyponatremia (abnormally low levels of sodium in the blood) may occur. The effects of intermittent, occasional use are uncertain. Rarely, liver failure occurs.
Chronic, repeated use may cause problems similar to those of amphetamines, including dependence. Some users develop paranoid psychosis. Decline in mental functioning may also occur with repeated, frequent use.
Treatment for acute toxicity and dependency is similar to treatment for amphetamines, although treatment for acute overdose is less commonly needed.