Ketamine began to be used in the 1960s as anesthesia in operating rooms and on battlefields, in addition to being a recreational drug consumed at parties. “But, about 20 years ago, a team of scientists in the United States accidentally discovered that in very low doses can quickly improve the mood of patients with depression”explains Hailan Hu, professor and executive director of the Neuroscience Center at the Faculty of Medicine of Zhejiang University (China).