It's tough being young, famous or no. It's a confusing and painful time, even in your '20s. Some people end up turning to destructive means to ease their pain.
You know, I listened to an interview with Lindsay Lohan recently. She reminded me of how Drew Barrymore used to sound when she was a teenager and had a sort of "party" lifestyle. Jaded and depressed. Drew, from what I've seen, doesn't sound like that anymore; obviously she's older now and has gotten her life together. Hopefully Lindsay will be able to eventually deal with her problems.
And I agree, ilikemuppets, celebs have some of the same problems ordinary people do, we're just hearing about it more. Plus their Hollywood lifestyle often supports bad behavior.