4 yr old grandson asked to leave 2 different daycare's

My grandson has been "kicked out" of 2 different preschools and has started another.  The teachers say that he has trouble transitioning.  He will hit, run out the door, fight, and is uncontrolable.  Is this a form of ADD?  It does not happen as often at home.  He is smart and doesn't seem to have any other problems.  His mother is freaking out thinking that he has Autisum or Bypolar disorder.  What do you think she should do?  Help before he is "out' of another school.

[Kevin Kennedy, Ph.D.]

He should be evaluated by a child psychiatrist. There may some hyperactivity and it is not out of the question (due to the aggressive behavior) that a juvenile onset bipolar disorder is present. Suffice it to say that the situation invites evaluation.