I have/had an anxiety disorder related to school, "school refusal". I would have horrible attacks before school, at school, and after school (most times not all in the same day). Starting in 6th grade, I missed the 3rd nine weeks of school for several years, because being in school for the first part of the year drained me so badly, that I couldn't cope and missed school. Mom called is "Febuitius" because that is when it started each year. I suffered chest and stomach pains, throwing up, being tired ALL the time when I didn't even have mono. Eventually I dropped out, because I couldn't cope anymore. If I hadn't of dropped out, I probably would have had a break down (no, I'm not kidding). If he is having these problems, when he is in school, maybe something is happening at school to cause anxiety? I didn't get my diagnoses until years after I dropped out (my old therpist didn't tell my parents, nor myself...) but if I had, it could have been treated. I guess I'm saying, if you can't find a physical reason behind this, maybe it isn't physical?