MDMA (contracted from 3,4-methylenedioxy-methamphetamine) is a psychoactive drug of the substituted methylenedioxyphenethylamine and substituted amphetamine classes of drugs that is consumed primarily for its euphoric and empathogenic effects. Pharmacologically, MDMA acts as a serotonin-norepinephrine-dopamine releasing agent and reuptake inhibitor.MDMA has become widely known as ""ecstasy"" (shortened to ""E"", ""X"", or ""XTC""), usually referring to its tablet form, although this term may also include the presence of possible adulterants. The UK term ""Mandy"" and the US term ""Molly"" colloquially refer to MDMA in a crystalline powder form that is relatively free of adulterants. ""Molly"" can sometimes also refer to the related drugs methylone, MDPV, mephedrone or any other of the pharmacological group of compounds commonly known as bath salts.Possession of MDMA is illegal in most countries. Some limited exceptions exist for scientific and medical research. In 2013 between 9 and 28 million people used ecstasy recreationally (0.2% to 0.6% of the global population between the ages of 15 and 65). This was broadly similar to the number for cocaine, substituted amphetamines, and opioids, but far fewer than the number of cannabis users. It is taken in a variety of contexts and is commonly associated with dance parties (or ""raves"") and electronic dance music.MDMA may have health benefits in certain mental disorders, but has potential adverse effects, such as neurotoxicity and cognitive impairment. More research is needed in order to determine if its potential usefulness in posttraumatic stress disorder (PTSD) treatment outweighs the risk of persistent neuropsychological harm to a patient.