I have two sons with Autism. One has been diagnosed with migraines. Does anyone in your family have a history of migraines? If so, there is a good chance that your son may have migraines. He responds well to feverfew daily. I use herbs as much as possible. He also does well with Grapine and Kava-Kava, when he is anxious. Food coloring, especially red and yellow, seem to trigger anxiety attacks followed by depression, for my children. I was told this by the cheif of neurology at Children's Hospital. It works, but it takes about two weeks to a month to help, and you must be very stringent with checking his food. I think that my other son also has migraines, although he is aphasic and harder to diagnose. I also discovered that one of my sons stops banging his head and holding his ears when he gets Cranio-Sacral Therapy from a Physical Therapist at least twice a month. It really helps his speech, as well. He is woozy for a little while afterwards, and sometimes sleeps the next day. It has a profound positive effect on him, overall. It may not help your son, but it is worth trying. Do try witholding food coloring, as well. Also, most migraines usualy show up in early adolecence. Your son's age may be an indicator, also. Please check for such things as Leaky Gut Syndrome. Your son may have an intolerence for gluten and/or casin and the resulting bowel pain apparently worsens the tendency for headbanging in Autistic children. There is a GFCF diet website for parents of children with this problem. It's very helpful.