Mark,

Do you think the same can go for experiencing a symptom from over-exertion? Yesterday I had an extensive and pretty intense discussion with my girlfriend that triggered severe fatigue, probably because we were going over some pretty abstract stuff that forced me to think in multiple layers and hold several thoughts in my head at once. Today I feel a little groggy and "fuzzy around the edges", but I suppose that could just be a symptom coming from anticipational anxiety? My thinking goes along the lines of that the brain has experienced getting worse after experiencing severe symptoms, so the anxiety kicks in as soon as one experiences a symptom, however slight, because one can be fearful of getting worse or not getting better soon enough.

Really interesting stuff, if you have any literary recommendations on the topic I'd be glad to read up on it.