Frankie earned the reputation of being the "terrorist of the 4 year olds" at his daycare center. He has been expelled from 2 other daycare centers and is on notice with the current one. If Frankie's behavior does not improve, he will not be invited back. Frankie punches or bites other children so he spends a lot of time in the timeout corner. On the playground, he pushes the other children off the swings for no apparent reason. Frankie squeezes the class pet rabbit and when he thinks no one is looking swings it by the tail despite being told how much this hurts the animal. According to his mother, "Frankie has been hard to manage even when he was an infant." Frankie's diagnosis is: