Ketamine has been available to medical professionals and vets as an anaesthetic since is was first synthesised in 1962. The benefits in medical scenarios are that it can calm and disassociate a patient while maintaining heart rate. It has been widely used as a narcotic since its introduction to the rave scene in the late 1980’s and became popular due to its sedative and hallucinatory effects.
Extended Ketamine use can lead to depressive episodes, even though it has been experimented with as a treatment for depression! As with most, now illegal, drugs, Ketamine began life as a medicine and became a narcotic.