I didn't have a rotten childhood but still I needed a fantasy world. Sometimes it is similar to real life, like rehearsing real life, other times it is like real life but I get everything set for me and my enemies get theirs in various ways. Sometimes it is like being somewhere else with other people around and things that could occur. I have done this type since I was a kid. If I didn't I couldn't fall asleep and it holds true sometimes today too.
I will never live totally separated from my fantasies. Sometimes my fantasies have helped me in life showing different ways a thing can play out.
If my fantasy world is useless to real life I comfort myself it plays an important part in my creative writing. If you have very interesting fantasy worlds, why not make them a story?