Amy, welcome! I'm glad you found us.
According to The Bipolar Child (and our own psychiatrists), 30 to 50 percent of young children who start off with a diagnosis of depression end up actually having bipolar disorder. Many of these depressed kids are treated with SSRI antidepressants like Zoloft and end up in worse shape because antidepressants destabilize them and make them manic, angry, aggressive and completely uncontrollable. I have lived this scenario with two of my kids who took SSRIs (Zoloft in my son's case and Paxil in my daughter's case). They are now on mood stabilizers and doing a whole lot better.
Your son is on two antidepressants (Zoloft and Strattera), which actually could be making things much worse. Abilify is an atypical antipsychotic that treats the mania associated with bipolar disorder, but it would not be enough to offset the destabilizing effects of Zoloft and Strattera. If your son has BiPolar (BP), he would need to be treated with a first-line mood stabilizer (Lithium, Lamictal, Depakote, Tegretol, Trileptal).
I would strongly recommend a new evaluation with a board-certified child psychiatrist who has experience treating kids with BiPolar (BP). It's imperative that you get your son on the right treatment if he indeed has BiPolar (BP) or things will only get progressively worse.
Again, welcome. I wish you luck on your journey.
