According to Wikipedia:
“Some people suggest that hypochondriasis is a “mild form” of paranoid schizophrenia, as patients tend to show a paranoid framework in which the target is their body]]. Also, the persistent paranoid feeling about illness can be regarded as delusion from reality.”
There is no source for this and in my brief attempts to gather further information I haven’t found anything of direct relevance. I can see, though, that false beliefs about the body are frequently listed as a possible symptom of Major Depression with Psychotic Features (“Psychotic Depression”) as well. It also gets mentioned with depressive phases of bipolar disorder. I think there is something in the idea that hypochondriasis has a psychotic or delusional element, although I doubt that it is a form of schizophrenia.
I would say that my perception of reality can become distorted in the grips of hypochondriasis. When I believe I have some illness for a prolonged period, I may eventually develop strange ideas behind it. I have wondered whether I am being punished by God or, even more bizarrely, rewarded by him. At one point I became afraid that it was the end of the world (Harold Camping scared me, even though on a normal day I’m perfectly capable of telling that he is the delusional one) and figured that my death may have been made to coincide with this in order to teach me a lesson about morality. This all has a tinge of “persecutory delusions” and “delusions of grandeur”. On the other hand, it is difficult to say to what extent I believed these things or whether I was just scared, “what if?”. I certainly had some insight into the irrationality of my ideas. I have been repeatedly assured that I am not psychotic, although at times have suffered from some minor delusional thinking a la OCD, and that worrying that I might be is actually a symptom of OCD. How complicated this all is.
I still do not know whether hypochondriasis is currently considered to be a somatoform disorder or a disorder belonging the OCD spectrum. Psychiatrists I have spoken to seem to say that it is one or the other, although as far as I can tell it has plenty in common with both groups. It may pattern like OCD in terms of unpleasant obsessional thoughts and neutralizing compulsions and it has physical symptoms like a somatoform disorder, from common and misinterpreted symptoms to stranger ones where no other pathology is uncovered. I think it is accepted that severe OCD can lack insight and verge on psychotic. I’m not so sure about somatoform disorders; it has always seemed strange to me that they are not described as being delusional.
Well, as you can see, I have no idea what hypochondriasis really is. More and more it seems to me that diagnostic categories are arbitrary. I find the idea that hypochondriasis could have something in common with paranoid schizophrenia interesting because that suggests it crosses a lot of categories. Anyway, there just doesn’t seem to be as much information out there on hypochondriasis as I would expect. I believe it is much more than just “an excessive preoccupation or worry about having a serious illness” (again, Wikipedia).
If anyone reads this and wants to contribute at all, as is always the case, it would be very welcome.