Parents, is it possible for adhd symtoms to show up as early as 3 years old? What about manic depression, etc?

Are there any books or something that me and the mother, who is a friend; can get educated on as to what signs or symptoms I should look for. The child’s father is manic depressive and bipolar and I’m wondering is this an inherited trait or disease this child could be showing signs of having, [...] http://bit.ly/qz2ld5