Based on a lecture to the Autumn Scientific Meeting of the Association of British Neurologists and the British Neuropsychiatry Association, 3 October 2002 As both a physician and a politician, I was first touched by the question of how illness can affect the decision‐making of Heads of State or Government when I met the Shah of Iran in Tehran in May 1977.1 He appeared to be at the height of his power: self‐confident, and enjoying his global role in helping to determine world oil prices. It would have been a great help to have known then, and particularly a year later, that he had been suffering from chronic lymphocytic leukaemia. He had been diagnosed in April 1974 by the French haematologist Professor Jean Bernard, and eventually died from it in Cairo in July 1980. At that time, the Shah's own physician, Dr Abdol Karim Ayadi, asked Dr Bernard and his assistant Dr Georges Flandrin, not to tell the Shah he had cancer, which was then at Stage II and not requiring treatment. The Shah did not take chlorambucil until February 1975. Thereafter, Dr Flandrin flew 35 times in great secrecy to Tehran before the Shah was forced to leave in January 1979. In 1977, his doctors told the Empress he had leukaemia or cancer, but still those two words were never used to the Shah, who was told that he had Waldenstrom's disease. Apart from being tired, he had no obvious signs apart from an enlarged spleen, until he noticed a swollen lymph node in his neck in April 1979, when in exile in the Bahamas. The Shah was then told he had cancer and was given nitrogen‐mustard, vincristine, procarbazine and prednisolone. His health deteriorated, and pressure grew for him to leave Mexico and be admitted to an American …