My son is 6 and is a sweet and adorable child, whose smile lights up the room. He is very bright and has an amazing aptitude for numbers. He's very friendly....but doesn't connect well with others. He's extremely stubborn and becomes obsessed with odd things (like the color red) and is willing to "fight to the death" to get things his way. He has been diagnosed with Pervasive Developmental Disorder (PDD)-not otherwise specified and is on Strattera and Buspar. He does well in school...but at home we have big problems with him. He and his older brother, who is 9, fight constantly (physically). The most concerning behavior is that lately he has found a lot of delight in torturing our new kitten. He has hurt her many times and she now cries whenever he comes near. We have tried punishment, social stories and lots of discussions. I'm at my wits end. I feel like I'm a patient person and can deal with a lot of his misbehavior...but hurting the cat has sent me over the edge. What should I do? Any ideas?