Successfully Rehabbed: Robert Downey Jr.
Robert Downey Jr. became a cocaine and heroine addict at the age of eight due to his father's heavy drug use. Downey knew he had a problem but he couldn't stop using--infamous describing his situation as, "It's like I've got a shotgun in my mouth with my finger on the trigger, and I like the taste of the gun metal." However, he got control of his urges and checked into rehab. Downey launched his career comeback in 2011 and has since appeared in blockbuster successes like 'Iron Man' and 'Tropic Thunder'.
Source: Bauer Griffin Online