After veteran Tony Macie came back from Iraq in 2007, he was diagnosed with post traumatic stress disorder (PTSD). Macie went to the Department of Veterans' Affairs (VA) "on and off" and tried the standard therapy.

"And then I kind of just fell off the radar, secluded, and did my own thing and got really dependent on a lot of the meds," Macie explains in the video below by the Multidisciplinary Association for Psychedelic Studies (MAPS). The retired sergeant then became part of a clinical trial organised by MAPS that was testing an unusual substance in an attempt to heal people who hadn't responded to traditional therapies for PTSD.

That substance, MDMA (commonly referred to as 'Molly'), is the pure form of the illegal party drug known as ecstasy. (Most non-research substances that are sold as ecstasy or Molly are not actually pure MDMA and can be significantly more dangerous.) The trial pairs MDMA with psychotherapy.

"One of the first things I said when it kicked in was 'this is what I've been looking for'," Macie says in the video. "I reconnected with myself and did a lot of internal work, and afterwards it was like a huge weight was lifted off my shoulders."

Macie isn't the only one to find relief. One of the early studies conducted by MAPS showed that 83 percent of the study participants no longer showed signs of PTSD two months after treatment, and long-term follow-ups conducted an average of four years later showed that most of those benefits stuck.

That was a proof-of-concept study, with just 20 participants, all of whom had psychotherapy as well. (Twelve were given MDMA, and eight were given a placebo; 25 percent of those on the placebo improved, too.)

Though small and preliminary, the results were encouraging enough to help lead to Phase 2 clinical trials – the second in the three sets of human trials required before the Food and Drug Administration (FDA) will consider a new drug for approval.

In March, MAPS announced that their Phase 2 clinical trials are coming to an end. These trials consisted of at least eight studies that Brad Burge, the director of communications for MAPS, recently told Inverse treated 136 people using MDMA-assisted psychotherapy for PTSD.

While most of these studies are still technically ongoing – the researchers are still collecting data and have not yet published their complete results – the final experimental treatment in all of these studies has already been given. Until the studies are published and analysed, however, we won't know how effective MDMA-assisted psychotherapy was compared to current treatments or a placebo.

But according to MAPS, the organisation is meeting with the FDA to plan Phase 3 trials, which would be the final tests involving hundreds of people that are conducted before the FDA decides to approve a new medication.

Burge told Inverse that the organisation believes they are on track for getting MDMA approved as a therapeutic treatment by 2021.

"Phase 3 starts around 2017, and it will take four to five years to finish. So that will put it at early 2021 for FDA approval," he said.

MAPS is mostly raising money themselves to fund what they describe as a roughly $20 million plan to complete these trials, which are largely not of interest to pharmaceutical companies since the patent on MDMA has expired. That will mean significant fundraising is required.

The nonprofit currently has $9.1 million in assets; more than $5 million of that is a bequest from a long-time board member that has been earmarked specifically for those Phase 3 trials. That still leaves a $15 million gap. Last year, MAPS raised a total of $2.99 million from 2,500 donors. It noted in its most recent annual report that "substantially increasing our donor base" will be necessary to to move forward with Phase 3 trials.

It's only after those trials wrap up that we'll know for sure whether using MDMA to treat PTSD is safe and effective. MAPS calls making that happen its "top priority".

The group is also conducting research testing the efficacy of MDMA-assisted therapy to treat social anxiety in autistic adults and to treat anxiety associated with life-threatening illnesses like cancer.

"It's a really interesting and a very powerful new approach," former National Institute of Mental Health director Thomas Insel told the San Francisco Chronicle. "It's not just taking MDMA. It's taking it in the context of a treatment that involves improved insight and increased skills and using this in the broader context of psychotherapy."

As Macie says in the MAPS video, "this tool, it may not be the end all, but it [could] be a tool that can help a lot of people drastically".

This article was originally published by Business Insider.

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