If you ask Dr. Mathew Hoskins, a U.K. psychiatrist and researcher, post traumatic stress disorder is among the most horrifying mental illnesses out there. “PTSD is terrible,” he says. “You’re living with the worst thing that’s ever happened to you many moments of every day for as long as you have the illness.” And there’s also this: The gold standard of care, talk therapy supplemented with medication, helps only three out of five patients. No wonder Hoskins is looking for better treatments. No wonder he was willing to serve as a guinea pig for MDMA treatment trials.

As it stands, the best drug therapies available are only slightly better than a placebo when offered without additional help. That means many PTSD sufferers, a group that constitutes seven or eight percent of Americans at some point in their lives, are left to suffer through vivid memories, flashbacks, and nightmares. They often isolate themselves in an effort to avoid situations that might trigger their trauma, and they are hypersensitive to emotional things unrelated to their traumatic memories.

“We urgently need new treatments,” says Hoskins, who has been studying PTSD for the last five years. “MDMA is probably the most promising thing that I’ve heard of.”

But there’s a big difference between promising and legal. For MDMA treatments to enter the mainstream, they need to make it through large scale Phase 3 Food and Drug Administration trials. The research necessary to get there is being funded by the Multidisciplinary Association for Psychedelic Studies, which aims for medical legalization by 2021. In order to reach that goal MAPS needs therapists trained to guide patients through the treatment and many therapists, Hoskins included, want to know exactly what they’d be prescribing. Fortunately, MAPS has received approval to give therapists a course of MDMA assisted therapy as part of their training. Hoskins was one of the first to go through the process.

Hoskins travelled to South Carolina last year to drop MDMA and talk about his feelings. The sessions were led by Michael Mithoefer and Ann Mithoefer, the two principal investigators in the study. Hoskins underwent two rounds of therapy, a couple of days apart, one with MDMA and once with a placebo. The placebo round, which came first, was nice and relaxing, but the MDMA session was something else.

“It was beautiful,” Hoskins recalls. “It was absolutely amazing.” After taking the pill, he put an eye mask and headphones on, and lost himself in the soothing music that played. In about two hours, the effects of the drug was really kicking in.

“I’ve got no recent traumatic stress — nothing hugely stressful going on in my life — so I wasn’t expecting to start processing things,” he says. “But things started coming up. And every now and then I would take the eye mask and the music off and I would talk about some things that have happened in my family or stresses in work. Then, right at the peak of it, the main thing that I wanted to talk about was my friend Alex, who died in a plane crash quite a few years ago. That was what came up quite strongly for me, reliving memories quite vividly of how horrible that was and how it was a lot to work through at the time. I wasn’t really expecting that to come up, but it did, and it was really therapeutic for me.”

When he came down, he was hungry. He ate chicken and waffles at 6PM and was in bed by 10PM.

“What really surprised me was the following day,” he remembers. “I just felt incredible. And that kind of lasted for about a week. It might have been because it was beautiful and sunny in South Carolina and we had lots of fun things to do in between the sessions, but I definitely had an afterglow…. I think that’s what they’ve seen in a lot of their studies as well: People don’t really get the come down effect when they take it in that setting, very early in the morning.”

Hoskins completed the sessions along with two fellow UK researchers, psychiatrist Ben Sessa and psychologist Chrissie Wilson, who reported similar experiences. The three of them have a special reason for wanting to be a part of this work: They are planning their own research study, one that will image the brain of people with PTSD both on and off MDMA. It will follow up on groundbreaking work.

In 2010, the Journal of Psychopharmacology published the results of a clinical trial that studied the use of MDMA-assisted psychotherapy in patients with chronic PTSD. Participants in the double-blind study had suffered from the illness for an average of 19 years, and had found little relief from talk therapy and drugs. The MDMA treatment involves patients taking the drug in a comfortable setting, where they can turn inwards and work through things in their own head, and talk them through with therapists as they feel inclined. Although the sample size was small, the results were astounding: Of the twelve patients who received two rounds of MDMA assisted therapy, 10 saw their symptoms reduced so dramatically that they no longer met the criteria for a PTSD diagnosis. A follow up study found that benefits from the treatment were sustained for almost all participants years later.

It’s unclear exactly how it works, although possibly the drug acts on the brain in a way that lets the patient revisit the trauma without becoming overwhelmed by it, thus allowing the patient to process past events, see them in a new light, and move on.

“We felt quite strongly that we should go through the therapist’s training,” says Hoskins. “We’re asking our participants in our study to do really quite a lot. It’s quite stressful going into an fMRI — a brain scanner — for an hour, anyway. You’ve got to sit very still. And we’re asking them to actually relive their trauma in the scanner. If they’re not on a drug, that’s quite a big ask.”

The experiences in South Carolina helped the researchers refine aspects of their study protocol and get a better handle on what their patients will go through on the drug. Hoskins wants to be able to use MDMA to help cure many PTSD sufferers, but his first responsibility remains to the people in front of him.

The biggest barrier that remains to get these treatments out to the people who need them is the resistance of governments to deal with banned substances, says Hoskins. But he’s hopeful that with these promising results in hand, research funding and momentum will continue to build one dose at a time.