The BBC reported an inquest concluded the 40-year-old celebrity hanged himself after ingesting a mixture of cocaine, tranquilizers and sleeping pills.
The designer, whose death came just days after his mother's, had a history of depression and anxiety and attempted suicide twice in 2009, the British broadcaster said.
"The balance of his mind was disturbed," the BBC quoted coroner Dr. Paul Knapman as saying in announcing the suicide verdict. "It seems that he had a history of self-harm and, no doubt fueled by cocaine, he resorted to desperate measures to end his life. It's such a pity for a man who, from a modest start, climbed to the top of his profession only to die in such tragedy."