I am pretty certain that eventually all psychiatric disorders will be revealed to have genetic, physiological underpinnings.

I believe I have experienced this one when I was exposed to formaldehyde years ago. I experienced severe anxiety symptoms along with swollen lips and tongue.

was focused on Behavioral Medicine and several courses were devoted to the connection between allergies and behavior, especially food allergies.

There is a lot of literature in journals about this.

Did your symptoms abate, or are they still bothering you?

Sometimes an allergen elicits an extraordinary response from the immune system that makes you susceptible to other triggers.

Unfortunately this is an area that there are few experts in, but holistically oriented physicians are more likely to understand the connections.

Mast cell disorders sometimes underlie generalized allergic responses, if you are having those.

Is the cause hiding among the food deprived?

To me, the evident pattern of the persistently severely overweight or persistently severely underweight will eventually be found to be caused primarily by dna, bacteria or viruses, and/or the microbiome. The psychology to me seems secondary, more symptom than cause.

I think the results of treatment loosely support this hypothesis. People behave like they're underlying condition is not really being treated and are often only ever able to achieve short-term improvement with considerable interventions but rarely are able to keep this up long-term.

My experience talking with people who are very over or underweight is that their appetite corresponds strongly with their weight.

The very underweight have appetites that shut down quickly, making eating further very unpleasant for them. Conversely, the very overweight have strong appetites, making limiting intake very uncomfortable.

Though people don't like to think of it this way, much of our thought processes are epiphenomena of the physical and chemical and biological activity going on in our bodies.