Sorry about your experience Mati, I too experienced similar stuff. My Mother didn't know how to handle it when I needed her. I remember once, I was so unhappy that I cried all afternoon, I felt so unhappy, she came into my bedroom, I thought she was going to comfort me, but she told me to stop feeling sorry for myself and walked out.
As for your wishes to be dumb, when you were a kid? Well, when you are in such a situation, it is only human nature to find ways of coping. We do this on a subconscious level to extents we may never come to know. It sounds like you were just trying to work things out consciously... saying to yourself, well if I were dumb, then it would solve my problems... sad