I had a JW family member who got addicted to antidepressents. She went to a shrink, who switched her medicine, and she went to an AA type program for a few months. She never got off a pill addiction, but did manage to switch medicines. She felt guilty about going to the AA type program. It was held in a Baptist church and they all prayed to the wrong "God" at the beginning and end of every meeting - even though it was a completely non-denominational program. So, she stopped going.
I also knew a JW who was a schizoprenic (spelling ?). He was openly on meds, and had to be placed in a half-way house becuase he couldn't life in a normal home. The brothers had to stop him from going into service because he was just too wierd to send to the public door. All the JWs just said, "Won't in be nice in Paradise when Brother Schizo is made perfect..." They pretty much accepted him, which was good...because he was WAAAAAYYYY out there. Even when he went into the hospital, the Friends still visited him.
I think going to a shrink is a "tsk, tsk" behind the scenes show of weakness (especially if its for something not well understood as an open problem...like ADHD), but I don't think anyone will overtly say much to the child.