I think it impacted greatly, not being a normal child, always being locked up in a shack during the great parts in his childhood. While everyone else was enjoying their time at Hogwarts, Remus was always concerned he would attack someone. If it weren't for his friends he probably would have but since DD trusted him so much and Remus didn't want to break that trust, he went inside himself and found inner strength which propelled him into what he is today.

When he was younger before school he was probably sheltered away from the other children, never going out during the night for sleep-overs or parties. He had to learn how to be independant at such a young age he doesn't know what to do now. I give him a lot of credit for being so couragous, and never giving up hope. There's no cure for it and he's moved on, now if only he would go out with Tonks...lol