New developments in actor Matthew Perry’s death are shining a light on the ethics and efficacy of using ketamine as a therapeutic drug. To learn more about the promise and pitfalls of ketamine treatment, CNN’s Chief Medical Correspondent Dr. Sanjay Gupta turns to David Feifel, one of the first clinicians in the country to use ketamine to specifically treat depression. Learn more about your ad choices. Visit podcastchoices.com/adchoices