King George III and porphyria: a clinical re-examination of the historical evidence.

The diagnosis that George III suffered from acute porphyria has gained widespread acceptance,but re-examination of the evidence suggests it is unlikely that he had porphyria.The porphyria diagnosis was advanced by Ida Macalpine and Richard Hunter, whose clinical symptomatology and historical methodology were flawed.They highlighted selected symptoms, while ignoring, dismissing or suppressing counter-evidence.Their claims about peripheral neuropathy, cataracts, vocal hoarseness and abdominal pains are re-evaluated; and it is also demonstrated that evidence of discoloured urine is exceedingly weak. Macalpine and Hunter believed that mental illnesses were primarily caused by physical diseases, and their diagnosis of George III formed part of a wider agenda to promote controversial views about past, contemporary and future methods in psychiatry.