Cambridge students paid £250 to take ketamine

A neuroscientist has defended an experiment in which Cambridge University students were paid £250 to be injected with the hallucinogenic drug ketamine, most commonly known as a horse tranquiliser or an anaesthetic, but increasingly known on the streets as a rave drug.

Professor Paul Fletcher's researchers injected 15 participants with ketamine as part of a study into treatments for schizophrenia. His findings are due to be published in the January 2011 edition of Biological Psychiatry, the official journal of the Society of Biological Psychiatry.

The Times reports that one post-graduate student who took part in the study found the experience disturbing. "After they increased the dose I began to hallucinate," she said. "It made me feel scared. It felt like the bed was floating up and I felt very disorientated.

"I needed the money at the time and I wouldn't do it again."

John Mitchell, a spokesman for Rehab Guide, complained: "This is encouraging people to use ketamine for monetary reward," he said. "It's immoral. That's just a personal opinion but it's a very dangerous game."

But Prof Fletcher has denied that the experiment left the students at risk of any ill effects. He and his PhD assistant Hannah Morgan have issued a statement saying: "All participants undergo intensive screening beforehand, in terms of their history of physical or mental illness and of past drug abuse.

"We would not do this work if we considered that there was an unacceptable risk to participants."

However, it is generally accepted that regular ketamine abuse can result in panic attacks, depression and exacerbation of pre-existing mental health conditions - and one of the 15 participants in Prof Fletcher's trial did not own up to a previous mental illness.

Fletcher and Morgan responded in their statement: "Interestingly, he reported that he had been feeling very well and cheerful since participating in the study, though this is likely to be quite by chance rather than due to any therapeutic effect." ·