MDMA (3,4-methylenedioxy-N-methylamphetamine; methylenedioxymethamphetamine) is an entactogenic drug of the phenethylamine and amphetamine classes of drugs. In popular culture, MDMA has become widely known as "ecstasy", usually referring to its street pill form, although this term may also include the presence of possible adulterants. The terms "molly" (allegedly derived from "molecule") and "mandy" (a corruption of "MDMA") colloquially refer to MDMA in crystalline and/or powder form, usually implying purity.

MDMA can induce euphoria, a sense of intimacy with others, and diminished anxiety. Many studies, particularly in the fields of psychology and cognitive therapy, have suggested that MDMA has therapeutic benefits and facilitates therapy sessions in certain individuals, a practice for which it had formally been used in the past. Clinical trials are now testing the therapeutic potential of MDMA for post-traumatic stress disorder (PTSD) and anxiety associated with terminal cancer.

MDMA is criminalized in most countries, though some important civil society initiatives, such as the Global Commission on Drug Policy, are not concerned with putting a stop to it, but with educating the public about the drug, and its possession, manufacture, or sale may result in criminal prosecution, although some limited exceptions exist for scientific and medical research. For 2008 the UN estimated between 10–25 million people globally used ecstasy at least once in the past year. This was broadly similar to the number of cocaine, amphetamine and opiate users, but far fewer than the global number of cannabis users. It is taken in a variety of contexts far removed from its roots in psychotherapeutic settings and is commonly associated with dance parties (or "raves") and electronic dance music.

Alexander "Sasha" Theodore Shulgin (born June 17, 1925) is an American pharmacologist, chemist, artist, and drug developer.

Shulgin is credited with the popularization of MDMA, commonly known as ecstasy, in the late 1970s and early 1980s, especially for psychopharmaceutical use and the treatment of depression and post-traumatic stress disorder. In subsequent years, Shulgin discovered, synthesized, and bioassayed over 230 psychoactive compounds. In 1991 and 1997, he and his wife Ann Shulgin authored the books PiHKAL and TiHKAL on the topic of psychoactive drugs. Shulgin discovered many noteworthy phenethylamines including the 2C* family of which 2C-T-2, 2C-T-7, 2C-E, 2C-I, and 2C-B are most well known. Additionally, Shulgin performed seminal work into the descriptive synthesis of compounds based on the organic compound tryptamine.

Shulgin was born in Berkeley, California to Theodore Stevens Shulgin (1893–1978) and Henrietta D. Shulgin (1888–1960). Theodore was born in Orenburg, Russia, which is just north of Kazakhstan, and immigrated to the United States in 1923, while Henrietta was born in Illinois. Both Theodore and Henrietta were public school teachers in Alameda County.

David John Nutt (born 16 April 1951) is a British psychiatrist and neuropsychopharmacologist specialising in the research of drugs that affect the brain and conditions such as addiction, anxiety and sleep. He was until 2009 a professor at the University of Bristol heading their Psychopharmacology Unit. but since then he has been the Edmond J Safra chair in Neuropsychopharmacology at Imperial College, London. Nutt was a member of the Committee on Safety of Medicines, and was President of the European College of Neuropsychopharmacology.

Nutt completed his secondary education at Bristol Grammar School and then studied medicine at Downing College, Cambridge, graduating in 1972. In 1975, he completed his clinical training at Guy's Hospital.

He worked as a clinical scientist at the Radcliffe Infirmary from 1978 to 1982 where he carried out important basic research into the function of the benzodiazepine receptor/GABA ionophore complex, the long term effects of BZ agonist treatment and kindling with BZ partial inverse agonists. This work culminated in a ground-breaking paper in Nature (journal) in 1982 which described the concept of inverse agonism (using his preferred term, 'contragonism') for the first time. From 1983 to 1985, he lectured in psychiatry at the University of Oxford. In 1986, he was the Fogarty visiting scientist at the National Institute on Alcohol Abuse and Alcoholism in Bethesda, MD, just outside of Washington, D.C. Returning to the UK in 1988, he joined the University of Bristol as director of the Psychopharmacology Unit. In 2009, he then established the Department of Neuropsychopharmacology and Molecular Imaging at Imperial College, London, taking a new chair endowed by the Edmond J Safra Philanthropic Foundation. He is an editor of the Journal of Psychopharmacology.