Doctors are planning the first clinical trial of ecstasy in the UK, to see whether the drug can be beneficial to the traumatised survivors of child abuse, rape and war.

Ecstasy and other illegal drugs such as LSD and magic mushrooms are potentially useful in treating people with serious psychological disturbance who cannot begin to face up to their distress, some psychiatrists and therapists believe. But because of public fear and tabloid anger about illegal drugs, scientists say they find it almost impossible to explore their potential.

Professor David Nutt, the psychopharmacologist who used to head the government's Advisory Council on the Misuse of Drugs until he fell out with the Labour home secretary and was sacked, said: "I feel quite strongly that many drugs with therapeutic potential have been denied to patients and researchers because of the drugs regulation. The drugs have been made illegal in a vain attempt to stop kids using them, but people haven't thought about the negative consequences."

Nutt and the Taunton-based psychiatrist Dr Ben Sessa are two of the British scientists who hope to repeat an experiment on patients with post-traumatic stress disorder (PTSD) undertaken in the US which, although small, was successful and has caused some in the scientific community to think what was until recently unthinkable. It involved 20 people who had been in therapy and on pills for an average of 19 years. Twelve were given MDMA – or 3,4-methylenedioxymethamphetamine, the chemical compound found, often adulterated, in ecstasy tablets. The rest had placebo pills but were later also given the chance to take MDMA. Each one had a therapy session, lying back in a reclining chair in a pleasant flower-decorated room in South Carolina, wearing an eyemask.

Sometimes they listened to music on headphones and sometimes they talked to the therapist, all the while thinking about the events that had caused such profound distress that they had been unable to revisit it in past psychotherapy sessions.

The response rate was a remarkable 83% – 10 out of the 12 showed significant improvement two months after the second of two MDMA therapy sessions. That compared with 25% of those on the placebo. There were no serious side-effects and no long-term problems.

"I expected it was going to be effective," said Michael Mithoefer, the psychiatrist who ran the US study and carried out the psychotherapy with his wife, Ann. "I suppose we wouldn't have done it otherwise. But I didn't necessarily expect we'd find such statistical significance in that number [of people]. That was the icing on the cake."

The high number of troops returning with PTSD from Afghanistan and Iraq is attracting special attention to the study in the US. Only one of the 20 was a veteran, while the rest had suffered childhood sexual abuse, rape or other kinds of assault. Mithoefer's next study will be on veterans alone.

Nutt said PTSD is "an extraordinarily disabling condition and we don't have any really effective treatments. In order to deal with trauma, you have to be able to re-engage with the memory and then deal with it. For many people, as soon as the memory comes into consciousness, so does the fear and disgust".

Mithoefer said the participants did not appear to have joined the trial in hopes of some sort of high. "I don't think that was much of a factor at all. Some people were referred by their therapist and had never taken any drugs and were quite anxious about the whole thing and for them it was a last resort.

" Interestingly, several people said after their session: 'I don't know why they call this ecstasy' – because it was not an ecstatic experience. They were revisiting the trauma. It was very difficult and painful work, but the ecstasy gave them the feeling they could do it."

People spoke of getting past a barrier. One said: "I feel like I'm walking in a place I've needed to go for so long and just didn't know how to get there.

"I feel like I know myself better than I ever have before. Now I know I'm a normal person. I've been through some bad stuff, but … those are things have happened to me, not who I am … This is me. The medicine helps, but this is in me."

Another said: "I have respect for my emotions now (rather than fear of them). What's most comforting is knowing now I can handle difficult feelings without being overwhelmed. I realise feeling the fear and anger is not nearly as big a deal as I thought it would be."

Ben Sessa said he hoped to recreate the study in the UK but "with an added twist – lots of neuroimaging". The only brain scans that have been done are of recreational ecstasy users, whose drugs may be contaminated and who have probably taken other substances, too.The death in 1995 of Leah Betts after taking ecstasy, from drinking too much water in response to a campaign warning ravers of the danger of dehydration, had prevented rational debate or scientific advance.

MDMA, he said, "is not about dancing around nightclubs – it's a really useful psychiatric drug".

Nutt said it made him angry that MDMA and LSD had been banned before any doctor could establish their potential benefit. LSD was being tried among terminal cancer patients.

"When I started in medicine in 1969 they were starting to see some interesting data in the use of LSD to help people make sense of dying. I don't think it is fair that because a drug is misused it should be banned from use in medicine," he said Heroin has been around for a hundred years so although it is illegal for street use, at least we have got that..

Leading the movement to get MDMA licensed for medical use is Rick Doblin, the founder in 1986 in the US of Maps, the non-profit Multidisciplinary Association for Psychedelic Studies, which backed Mithoefer's trial. "I think the chances of getting a licence are excellent. We have demonstrated an excellent level of safety. It's worked. It's necessary," he said. "It is probably going to take 10 years and $10m to do it."

Doblin, whose organisation relies on philanthropic donors, has no idea where that money will come from. Nutt and Sessa, whose proposed trial in the UK would boost the chances of MDMA entering the (locked) psychiatric drug cabinet are waiting for a response to their modest grant application from one of the UK's leading medical research funders. Sessa is optimistic; battle-scarred Nutt less so. Ecstasy will for ever be controversial. "If we get the study funded and into the public domain," said Nutt, "the Daily Mail will try to have it banned."