Image caption Ecstasy has been illegal in the UK since the 1970s

Ecstasy may help boost therapy success in patients with post-traumatic stress disorder, say US researchers.

A small trial in 20 patients suggests use of the drug is safe and seems to improve the effects of psychotherapy.

The US team has now gained approval for a larger study in military veterans, but stresses more research is needed to confirm the finding.

A UK expert said it was difficult to draw any conclusions from such a small study and urged caution.

It is thought the clubbing drug reduces fear enabling patients to get more out of their therapy sessions.

Writing in the Journal of Psychopharmacology, the team said patients were selected on strict criteria - they had to have had post-traumatic stress disorder (PTSD) for many years and have failed with conventional treatments.

Doctors also excluded those with a history of psychosis or addiction.

In the trial, patients were offered two eight-hour psychotherapy sessions scheduled a few weeks apart, with 12 of them given a dose of ecstasy and eight a placebo.

Given that substance abuse is associated with many mental health problems including PTSD, I would want to see a lot more data before recommending this Professor Simon Wessely, Adviser in psychiatry to the British army

Two months later, 10 of the 12 patients given ecstasy responded to the treatment, the researchers said.

In contrast, just two out of eight patients offered a placebo showed an improvement.

There were no adverse effects from the use of the drug in the study, which was funded by the Multidisciplinary Association for Psychedelic Studies (MAPS).

MAPS is a non-profit organisation which aims to develop psychedelic drugs and marijuana into medicines to treat conditions where conventional medicines provide limited relief.

Study leader and psychiatrist Dr Michael Mithoefer said before ecstasy or MDMA, as it is clinically known, was used recreationally, hundreds of psychiatrists and psychotherapists around the world gave it to boost therapy.

Therapy sessions

He said: "Therapies for PTSD involve revisiting trauma in a therapeutic setting.

"But some reasons for it not being effective can be if the person is flooded with emotions they can't process or they have emotional 'numbing'.

"But MDMA seems to bring people into the optimal zone for therapy and seems to help them process the trauma and not be overwhelmed by feelings."

He said the next step was to start a planned trial in 40 military veterans before further studies in larger groups of patients.

The team are also following up patients to look at long-term effects and to find out if it increases the chance they will use the drug recreationally - but Dr Mithoefer said so far the results were reassuring.

If this were to be used more widely it would need special clinics equipped for long therapy sessions and overnight stays, he added.

Professor Simon Wessely, an expert in PTSD at King's College London and honorary consultant adviser in psychiatry for the British army, said due to the small size of the study it was difficult to draw any conclusions at this stage.

But he warned: "Given that substance abuse is associated with many mental health problems including PTSD, I would want to see a lot more data before recommending this."