Josef Stalin's judgment was severely impaired in his final years by a degenerative brain condition, one of the doctors who treated him on his death bed concluded.
In a previously unpublished personal diary, Alexander Myasnikov said Stalin suffered a progressive hardening of the arteries in his brain.
He wrote that he believed the condition clouded the Soviet dictator's ability to weigh up situations objectively and magnified his infamous paranoia and brutality.
"In essence a sick man ruled the state," the late Dr Myasnikov wrote in his memoirs, parts of which were published yesterday in Moskovsky Komsomolets, a Russian newspaper.
"I contend that Stalin's cruelty and paranoia, his fear of enemies, his losing the ability to soberly assess people and events, as well as his extreme stubbornness, were all in large part the result of the atherosclerosis of the arteries in his brain."
The condition was thought, in Stalin's case, to have been triggered by heavy smoking.
Stalin died on March 5, 1953, at the age of 74 after suffering a stroke. Dr Myasnikov saw the hardening of the dictator's brain arteries in the post mortem examination.
Dr Myasnikov's diary is thought to have been seized by the KGB when he died in 1965, but was recently recovered from the state archive by his family and is set to be turned into a book called 'I Treated Stalin'. (© Daily Telegraph, London)