MDMA (3,4-methylenedioxy-methamphetamine) is a popular party drug called Molly, and can be mixed with caffeine to make Ecstasy. It has an ability to temporarily boost mood, energy, and mental acuity through a dramatic upswing of the neurotransmitter serotonin. However, this upswing does come with some consequences as the body eliminates the excess serotonin.
While MDMA might be considered negative because it can be abused, responsible and controlled use of the chemical is being explored as a potential treatment for serious mood disorders.
Check out this video by AsapSCIENCE that explores the power of MDMA as well as the hazards that can come from long-term exposure.