did she have any illness ?
She had a nervous breakdown.
Vivien Leigh

In January 1953, Leigh travelled to Ceylon to film "Elephant Walk" with Peter Finch. Shortly after filming commenced, she had a nervous breakdown 
who played scarlet in gone with the wind Vivien Leigh who is he ? She was a British stage and film actress. where was she born ? Darjeeling, Bengal Presidency.
wiki:19600049
Vivien Leigh [SEP] 1951–1960: Struggle with mental illness
He dares too confidently ... but she hardly dares at all and is terrified of overreaching her technique and doing anything that she has not killed the spontaneity of by overpractice." In 1955, Leigh starred in Anatole Litvak's film "The Deep Blue Sea"; co-star Kenneth More felt he had poor chemistry with Leigh during the filming.