According to "Born to Be an Actor," Robert Downey Jr. had poor grades and school attendance coupled with drug and alcohol use. When he was told at the end of 11th grade he'd have to attend summer school to graduate, Downey Jr. decided to drop out to pursue an acting career in New York.

"For me, you know, growing up in school was just, you know, smoking pot all the time," said Downey Jr. in a CNN profile. "I consider myself someone who needs to express himself creatively, and acting seems to be the most lucrative and attention- getting way of working it out right now."