We have loads of experience here. DS spent 6-8 months last year on it, finishing in about September.
(After treatment since age 11 and pretty much 2 years on each of 2 and tibiotics (with trials of all the topical treatment in combination as well- don't forget usein both is often good).)
I gave him all the info (leaflets are on patient.co.uk for a start off) and told him he was an intelligent 15yr old and he was to make his own choice in conjunction with the dermatologist. Remember it is a "cosmetic" treatment and doesn't actually have to be used (I know the effects of acne are far reaching but still the option NOT to treat is there).
I stepped back completely and he and the dermatologist discussed on an adult level, he asked appropriate and searching questions and a joint choice to treat was made.
He didn't have an easy time on it at all, but he was aware that he was not likely to, and coped pretty well. THe hardest part really was the initial phase when we had lovely clearance fast, then relapse, as bad as ever before the dose as increased.
Side effects wise skin dryness was huge. His lips cracked/peeled constantly- he failed a french horn audition because the bleeding lips impaired his playing (nosebleeds too) He had muscle aches - as a keep sportsman that was tough too. He did choose start/stop of treatment to avoid rugby season though!
He never had any mood issues depression though, and couldn't see why he should given as he had chosen this drug to improve the very thing in his life that that DID depress him.
NOW:
He has amazing skin. Really total clearance of acne.
But.... he is still quite dry and burns easily still wears factor 50 in the UK. He see this as fair trade off for the acne being gone, but this could be a lifelong issue.
We know of 1 really severe dry eyes in a chap in his ?20s due to roaccutane too. He too , though he need ongoing drops etc, feels it's a reasonable deal.