It is very hard without a pediatric psychiatrist. We are fortunate here in Israel that the health care system works so well. Access to specialists is easy and inexpensive. I have Aspergers, and at least 2 of my three grandsons have Aspergers, ADHD, and sensory issues. One of the grandsons is only 4 and is on Ritalin currently and has been on other drugs previously that caused more problems than they helped. The Ritalin is supposed to be a short term thing to help him learn to modulate and focus. He and his brother are in a wonderful school that is geared to kids with these issues. Their language and social skills have improved a great deal in the last year or two. The elder now 6, may be mainstreamed into a regular school this year with a teachers aide present to assist with his adaptation.
I take Ritalin and I am taking Lyrica to modulate nerve pain from a chronic form of Guillain Barre disease. The reason I bring this up is one of the off book uses for Lyrica is to treat generalized anxiety disorder. I can tell you one thing for sure, Lyrica certainly has made me significantly more mellow and unfortunately also caused me some weight gain as well. Anyway you might want to investigate Lyrica as a possibility for the GAD.
BTW: Is there any chance your son is also Aspergers? His behavior might be linked to frustration stemming from the challenges of Asperger’s.