My Grandson Is Seeing A Psychiatrist And He Has Been

My grandson is seeing a psychiatrist and he has been place on depakote 250mg2x, imipram50mg daily(for bed wetting), zoloft 100mg daily, and now vistaril 25mg3x. He is deaf and autistic, high functioning spectrum. He is also ocd. He started skin picking several months ago, and we had not bothered with it as being a problem until recently. He was doing fair until they added the vistaril, but now he seems to be heading backward, nor does it help the skin picking.
What are the different interactions concerning this combination?