My son (now a freshman in college) used Accutane in the summer after his sophomore year - he did have very bad acne. It was under a very controlled environment with monthly visits to his dermatologist before the scrips would get refilled. Isn't for everyone.
I will say, if your contemplating doing this for your child, consider starting the treatment just before the school year ends because it can cause very intense skin dryness and flakiness and really, really chapped lips. This was hard for him to endure, but was thankful he didn't have to go to school in this condition.
By the time he started Jr. year he had skin like a baby's behind...so soft and clear. He still has very good skin, although I wish he would shave more often and not look like a hippie college kid...oh, yeah - he's a music major and IS a hippie college kid!
Edited to add: His younger sisters - one is a jr. and the other a freshman in high school, so far have not been plagued by severe acne. Both are prone to a few breakouts, but nothing serious. The jr. is on the pill because of issues with her monthly cycle and that has the added benefit of controlling acne breakouts.