Taking the Class A ecstasy drug, MDMA, can help veterans recover from Post Traumatic Stress Disorder (PTSD), according to a new study.
Scientists in the US have combined MDMA treatment with psychotherapy in an experimental pilot study that involved 22 military veterans, three firefighters and a police officer.
All had been diagnosed with PTSD as a result of their experiences during their service.
MDMA is the main chemical ingredient in ecstasy, a recreational drug that induces feelings of euphoria and heightened sensations.
It is an illegal Class A drug in the UK, which carries a maximum penalty of seven years imprisonment if caught in possession of it.
Participants were given doses of MDMA ranging between, 30mg, 75mg and 125mg.
On average, people in the two higher doses experienced less PTSD symptoms compared to those in the lower-dose group.
86% of participants in 75mg groups, 58% in the 125mg group and 29% in the 30mg group no longer met the diagnosis criteria of PTSD.
Lead researcher Dr Allison Feduccia, from the Multidisciplinary Association for Psychedelic Studies in Santa Cruz, California, said:
"Our study suggests that MDMA might help augment the psychotherapeutic experiences and may have a role to play in the future treatment of PTSD.
"However, we would certainly not recommend that individuals try these drugs for the treatment of psychiatric disorders without the support from trained psychotherapists."
MDMA was administered to the veterans during eight-hour long, specially adapted psychotherapy sessions.
Followed by an overnight stay in a clinic, seven days of telephone contact and another three, 90 minute psychotherapy sessions.
Researches wrote in the Lancent Psychiatry that side effects of the treatment included anxiety, headache, fatigue, muscle tension and insomnia.
Temporary rises in suicidal thoughts were also reported and one participant, with a history of attempting suicide, was admitted to hospital. However, they later completed the study.
Rick Doblin, Founder of Multidisciplinary Association for Psychedelic Studies, which is the organisation that funded the studies, says MDMA "does not have a high potential for addiction."
"MDMA was a therapy drug in the middle 70s to the 80s before it become a party drug, under the name 'Escasy' or 'Molly'."
"What made it so effective for therapy, before it was a party drug and why it's so effective now, is that it reduces activity in the amygdala - which is the fear-processing part of the brain, so when trauma is recalled the fear elements are muted so people can look at the trauma and process it."
He added: "If you were to design a drug to treat PTSD - MDMA would be it."
Mr Doblin says the effects of MDMA "diminish over time" so people who use the drug regularly, in recreational settings, "tend to self-limit after a year or so."
He reiterated that they were not worried veterans could become addicted to the drug: "The other main reason why we're not that concerned about addiction is that we're only giving MDMA three times."
Dr Michael Bloomfield, clinical lecturer in general psychiatry at University College London, said the study is "fascinating research" but more was needed to "tease out" the beneficial effects of MDMA.
During the trial, the participants and the clinicians were aware of how the doses of MDMA were being distributed.
Later participants were offered additional treatment from the drug, along with psychotherapy and they were told what they were receiving.
One year after the study, 16 of the 26 participants were no longer suffering from PTSD. Two received a new diagnosis.