It sounds like a tough situation, but I see a red flag or two. Now, I am not a doctor, but I was on Trileptal alone and I was having the same symptoms. I was not only depressed, but angry, irritable and hostile. It wasn't until I was put on Prozac and Seroquel in addition to Trileptal that I was able to experience stability. It has only been a few weeks, but the difference is like night and day.

Also, I wonder if it is time for a new p-doc. No p-doc should want to give up on a patient no matter how difficult the case is.

I hope you find relief for your son and remember to take care of yourself too.