Could it be possible that my son has been misdiagnosed for most of his life. Without writing a book on here, he has been diagnosed years ago as possible early onset bipolar, mood disorder, ADD, and learning disabilities not otherwise specified. Now they are saying he could be Pervasive Developmental Disorder (PDD) not otherwise specified. instead!!! What is this? and how could they have missed it all these years. He has been in counseling, on and off a variety of medications. and where we live it is he** trying to get evaluations much less help from the schools.