Until recently, prescribing Ecstasy, mescaline or magic mushrooms has been a guaranteed way for a psychiatrist to lose his research funding, job or even his liberty. But now, scientists are beginning to suspect that such illegal drugs may be the key to treating a range of illnesses, from post-traumatic stress disorder to depression.

These chemicals — which include the psychedelic drugs psilocybin, derived from magic mushrooms, and LSD, as well as Ecstasy — affect the way we think and behave, as well as causing hallucinations and mystical experiences. Yet a series of studies performed in Britain and the US is beginning to tease out their potential benefits. One, into the effects of Ecstasy, is featured in the controversial Channel 4 documentary, Drugs Live.

“People become very emotionally tender on Ecstasy, which makes you more responsive to psychotherapy,” explains Dr Robin Carhart-Harris, one of the experts involved. In the televised study, either a dose of Ecstasy or a placebo was given to 26 volunteers, including the writer Lionel Shriver and the former Lib Dem MP Dr Evan Harris. The scientists at Imperial College London then scanned their brains to see precisely where these drugs have an effect.

It was found that in the volunteers given the proper drug, the area of their brain involved in positive memories became more active, while another processing negative memories was damped down. “We think this would make it easier for patients to revisit a traumatic memory and overwrite or control it,” says Carhart-Harris.

This may sound radical yet half a century ago, research into the effects of psychedelic drugs was widespread and respectable. More than 1,000 papers were published looking at ways that psychiatrists could help patients with hallucinogenic chemicals. But then the walls descended, as a new anti-drug culture took hold, particularly in the US. In the 1970s, the Food and Drug Administration banned the use of LSD and related chemicals. Since then, research in the field has been effectively frozen, with recent years seeing a tentative thaw.

In both Britain and America, scientists can now get permission to use banned drugs in their research. But until very recently, few bothered, because funds were hard to obtain and such studies could damage a career. That attitude has been changing, with a growing lobby claiming that these drugs could be safely used to bring great benefit to patients.

“These drugs don’t appear to produce dependence,” says Dr Stephen Ross, director of the Division of Alcoholism and Drug Abuse at Bellevue Hospital in New York City. “Their ability to treat a range of addictive psychiatric and existential disorders is remarkable.”

The recent studies on Ecstasy and psilocybin were carried out under the Beckley Foundation (set up in Oxford by the Countess of Wemyss and March, Amanda Fielding, to initiate and fund studies into the effects of psychoactive drugs) and Imperial College Psychopharmacological Research Programme, with Professor David Nutt (a neuropsychopharmacologist at Imperial College London but better known as the former chairman of the UK’s Advisory Council on the Misuse of Drugs, who was fired for claiming that alcohol and tobacco were more harmful than Ecstasy and cannabis) as senior researcher. The Foundation is also collaborating with Johns Hopkins University in Baltimore in a study using psilocybin-assisted psychotherapy to treat cigarette addiction — the first study to use a psychedelic to treat dependency. The results from the pilot study show a 100 per cent success rate.

These drugs could be safely used in a clinical setting to bring great benefit to patients

The Beckley/Imperial psilocybin study, reported in the Proceedings of the National Academy of Sciences in January, was a major breakthrough. “One of my long-held theories about the brain has been that consciousness is directly linked to the volume of blood in the brain capillaries,” says Fielding, “and that drugs which intensify mental experiences, like psilocybin, increase that volume. However, the evidence shows a decrease in blood flow.”

The study found that blood flow dropped by 20 per cent in the brain’s communications centres. “These are the places where information from our senses is combined with our memories and expectations about the world,” says Fielding. “The result is the familiar consistent and coherent view of the world that we think of as normal. So it looks as though what the hallucinogens are doing is weakening that top-down control of our experience and allowing a freer, less constrained but more chaotic state of awareness to emerge. It may also be significant that the volunteers who reported the most vivid and powerful experiences were also those who had the greatest reduction in blood flow.”

Of more immediate practical use, however, was the finding that one of the “hubs” identified as being damped down by psilocybin — known as the “medial prefrontal cortex” — is already known to be overactive in people with depression. Now a clinical trial funded by the Medical Research Council will see whether psilocybin can help severely depressed people.

Of course, many think that substances such as mescaline and Ecstasy will always be beyond the pale. Anti-drugs campaigners have described the Channel 4 programme as “reckless and pointless”, claiming it will only glamorise drug use.

Yet the question of whether or not a drug should be legalised for uncontrolled public consumption is a quite different question to whether doctors should be allowed to prescribe the same chemical to treat their patients. It may be the case that one of the unwitting casualties of the War on Drugs is a cohort of people currently suffering intractable mental anguish, denied help simply because of the unfortunate associations between a potential cure and the psychedelic counter-culture that took root half a century ago.