A chemical analysis of the king's hair found concentrations of arsenic that are many times greater than normal, according to a study published today. Scientists believe the arsenic may have caused the onset of an inherited predisposition to an illness called porphyria, a metabolic disease that causes a build up of toxins in the blood. That could explain why King George III (1738-1820) suffered such severe attacks so late in his life.
The descent of the king into madness has been one of the most famous episodes in the history of the Royal family and was chronicled in an award-winning stage play and film, The Madness of King George. His bouts of deranged behaviour caused him to be put in a straitjacket, chained to a chair and forcibly fed a cocktail of medicines.
Professor Martin Warren of the University of Kent at Canterbury said there was little doubt the king was at risk of porphyria, but it was his exposure to arsenic that led him to have several severe attacks after the age of 50.
Writing in the journal The Lancet, Professor Warren and his colleagues say that the king was given an "emetic tartar" medicine made from antimony, which is known to have been contaminated with relatively high levels of arsenic. "The presence of arsenic in a sample of the king's hair provides a plausible explanation for the length and severity of his attacks of illness, and contamination of his antimonial medications is the probable source of the arsenic," Professor Warren said. "We propose that exposure to arsenic would exacerbate attacks of porphyria in a genetically predisposed individual. We feel the case for porphyria is as strong as we can make it," he added.
Historians who have studied the medical records of various descendants of King George, who died in 1820 after a 40-year reign, believe he suffered a genetic condition that led to the faulty production of a protein in the blood, causing his urine to turn red, as well as his madness. The many symptoms of porphyria include lameness, hoarseness, acute abdominal and limb pain, a racing pulse, insomnia, temporary mental disturbance and discoloured urine - some of which are known to have been suffered by the king.
During his reign, King George suffered five major episodes of prolonged and profound mental derangement but, curiously, they did not occur before middle age, which led the scientists to search for a possible trigger.
Professor Warren and his colleagues analysed a lock of the king's hair which had been kept at the Science Museum in London to see if he had been exposed to any toxic metals. They found that the concentration of arsenic in the hair was 17 parts per million (ppm), compared to typical levels of between 0.05ppm and 0.25ppm.
Professor Warren said there were other possible sources of arsenic, such as the powered wigs worn by the king, and that these may have caused the initial symptoms that were then exacerbated by his medicine. "It was really quite surprising to see such high levels of arsenic in his hair. I think this does offer such a wonderful solution to it all," Professor Warren said.