3,4-methylenedioxy-methamphetamine (MDMA), also known as Ecstasy, is a synthetic drug and derivative of amphetamine that alters mood and perception. It is chemically similar to both stimulants and hallucinogens and acts by increasing the activity of three brain chemicals: dopamine, norepinephrine, and serotonin. MDMA is illegal in most countries and, as of 2018, has no approved medical uses. Screening assays are generally qualitative and based on competitive ELISAs using urine, saliva, or blood samples.