"Most people turn to drugs because they have a sad story or mental illness, and society needs to recognize that." The source who came forward to reveal Diana's drug secret told us the letter was proof her coke taking had turned her into a "paranoid wreck." They said they had decided to reveal Diana's drug secret to show the world addiction can hit people from any walk of life. And it was at this point Diana "drew the line" and decided she needed to wean herself off cocaine. As Diana's drug taking increased, Michael offered his pal heroin.