Dr Sanjay Gupta: There's a group of outlawed drugs out there that are generating new interest among a growing number of doctors. Some of these drugs include things like MDMA also known as ecstasy, also LSD. Psychiatrists have (long) been fascinated by the properties of psychedelics. The U.S. military's efforts in the 1950s ... tested LSD as a potential weapon. But the interests in these drugs didn't stay in the lab. They trickled on to the black market and were soon outlawed. The pattern repeated itself with MDMA. Therapists tried it with patients. Millions tried it on their own. And in 1985, it was banned under federal law. Over the last decade, a small band of researchers wrangled permission to try again. This time giving MDMA during therapy sessions with patients who were suffering post-traumatic stress. DR. MICHAEL MITHOEFER, TESTING MDMA AS TREATMENT FOR PTSD PATIENTS: It was revisiting the trauma that was painful. The MDMA seemed to make it possible for them to do it effectively. GUPTA: Dr. Mithoefer has treated nearly 50 patients. He's currently working with veterans. RICK DOBLIN, MULTIDISCIPLINARY ASSOCIATION FOR PSYCHEDELIC STUDIES: People are able to look at traumatic memories, the fear is reduced, and then they're able to separate out it was happening then and not now. GUPTA: So, if they're going through counselling, for example, it could make that counselling more effective, they're not as paralyzed if you will by the memories that are being brought up? DOBLIN: We're saying that MDMA itself is not the medicine, it's MDMA assisted psychotherapy.