Ketamine, approved as an anesthetic in 1970, is emerging as a major alternative mental health treatment. But more than 500 clinics have popped up with little regulation, and treatment varies widely.

Researchers were able to mimic the mind-altering effects of the drug ketamine by inducing a particular rhythm in one area of the brain.

Doctors have a new option for suicidal patients. It's a fast-acting nasal spray containing a version of the anesthetic ketamine.