M.B.
This may not be quite the answer you're looking for, but modifying his diet might provide some improvement. For example, bipolar disorder has been associated with gluten intolerance (just google bipolar and gluten and you'll find tons of references).
There is a dietician in Plano area that has lots of experience (I think one of her degrees is in psychology) on looking at the impact of diet and similar problems (e.g. autism, etc.). Her name is Faye Elahi - her website is www.specialneedsnutrition.com.
There is also Dr. Block (www.blockcenter.com) in the mid-cities that specializes in treating folks with autism spectrum disorders. She is a world reknown expert on non-drug protocols for treating these problems. I think we're extremely lucky to have her in the area. She periodically has free educational seminars at her clinic.
As a personal note, I would have considered my older son on the autism spectrum as well, but since going on a GF/CF diet, he has really improved tremendously.
Best wishes.