THE Strange Case of Dr Jekyll and Mr Hyde was written by Robert Louis Stevenson under the influence of a hallucinogenic drug similar to LSD, according to new research.

Doctors believe the Scots author wrote the classic exploration of good and evil while being treated with a derivative of ergot, a potentially deadly hallucinogenic fungus.

The mould, which affects rye and wheat, caused mass poisonings during the Middle Ages. Victims suffered vivid hallucinations and convulsions, which were mistakenly believed to be symptoms of demonic possession. Many witch trials, including those in Salem, Massachusetts, in 1692, are believed to have been triggered by outbreaks of ergotism.

During the Victorian era, ergotine, a derivative of the fungus, was used by doctors to stop bleeding. Stevenson, who suffered from tuberculosis, was given injections of the drug to stop bleeding in his lungs.

Professor Robert Winston, the chair of the House of Lords select committee on science and technology, and Dr George Addis, a former consultant in medicine and therapeutics at Glasgow University, believe that the injections led to side-effects that created a “Mr Hyde-like” transformation in the author. Their findings will be revealed today in a BBC1 documentary.

They believe that they have found evidence in a recently uncovered letter, now held in Yale University’s archive, that shows Stevenson experienced spasms and hallucinations characteristic of an ergotine overdose.

In the letter, dated “end of August, early September 1885”, Stevenson’s wife wrote to William Henley, her husband’s friend and literary agent: “Louis’s mad behaviour . . . I think it must be the ergotine that affects his brain at such time.

“He is quite rational now, I am thankful to say, but he has just giving up insisting that he should be lifted into bed in a kneeling position, his face to the pillow.”

Two weeks later Stevenson began writing his famous work about the duality of human nature. The story recounts the adventures of Dr Jekyll, who takes drugs that separate the good and evil in his psyche. Although the doctor is purified, the evil Mr Hyde is created as a terrible side-effect.

Stevenson always claimed that the plot of Jekyll and Hyde came to him in a fevered dream while he was seriously ill. Yet in August 1885 his bleeding became so severe he was given at least one injection of ergotine, which is referred to in another letter.

In the BBC programme — The Adventures of Robert Louis Stevenson — Winston claims that ergotine was an important influence on Stevenson.

“Dr Jekyll and Mr Hyde is about drug taking and the power of drugs which overtake his body completely and drive Dr Jekyll in a way that really is completely alien to him,” he says. “Maybe that’s what Stevenson is feeling with the use of the drugs that he’s taking, particularly ergotine. Perhaps he becomes a Mr Hyde himself.”

Andrew Thompson, the documentary’s producer and director, said the doctors’ findings could lead to important insights into Stevenson’s influences.

“The fact that Stevenson was injected with such a powerful drug just a couple of weeks before the writing of his famous story about personality-altering drugs has to be linked.”

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