The trial saw the participants offered two eight hour psychotherapy sessions scheduled a few weeks apart, with 12 of the group given a dose of ecstasy and eight given a placebo drug.
The participants were carefully selected for the trial and had to have had PTSD for a period of many years and have failed with conventional medical treatment.
After two months, 10 out of the 12 patients given ecstasy were found to have responded very well to treatment, compared to just two out of the eight patients offered a placebo.
Though the research team has just been cleared to continue with another larger study in 40 military veterans, they have stressed that more research is needed in larger groups of patients to confirm their initial findings.
Study leader and psychiatrist Dr Michael Mithoefer pointed out that before ecstasy became known and banned for its recreational use, many psychiatrists and psychotherapists would prescribe it to boost the effects of therapy.
The researchers believe the drug works by reducing fear and subsequently allowing patients to get more from therapy sessions.
The research team are keeping track of patients from the first trial in order to gauge the long term effects of the study and whether use of the drug in a medical setting will increase the chance of it being taken for recreation. So far Dr Mithoefer has said the results are reassuring.