There have been suggestions that it might be the result of childhood abuse. There's also suggestions that it could be a late-onset problem, something that wasn't congenital.

This question is particularly vexxing because my memory of childhood is very limited.

• Alarm clock volume — As far back as I can remember, it was very difficult to get me to wake up.
• Parties — As far back as I can remember, I could only stay in parties for ~20 minutes before I had to leave (now, I realize it was because of sound and touch overload... back then, I thought I was extremely antisocial)