Growing up amid the tumult of the Cuban Missile Crisis and the Vietnam War, Rick Doblin says he became convinced that humanity was "crazy" and "inherently destructive".

Between 1950 and the mid-1960s more than 1,000 papers were published documenting 40,000 patients receiving LSD and other psychedelics for conditions like depression and addiction.

In college at the time, Doblin became convinced of the drug's power to enhance communication and healing after an MDMA session with his girlfriend. His original plan was to become a therapist working with MDMA.

Greer and his wife, a psychiatric nurse, treated more than 80 patients with MDMA between 1980 and 1985 .

In studies funded by MAPS, more than 50 percent of patients who completed MDMA-assisted therapy no longer had PTSD, compared with 23 percent of patients who received therapy with either a dummy pill or inactive dose of MDMA, depending on the study.

After MDMA treatment, McCourry was able to sleep through the night and stop taking antidepressants and anti-anxiety pills.

But MDMA has its own risks.

Tufts University psychiatrist Paul Summergrad says he wants to see more rigorous trials to confirm the benefits of MDMA and psilocybin.

These days, Doblin says he only occasionally uses MDMA for "therapeutic purposes".

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