when you begin to become a paranoid hypochondriac but still possess the rationality to question your thoughts, a few very good questions emerge:
did your symptoms emerge simply because you are a hypochondriac and the mind is so powerful that it's beliefs can become reality?
or were the symptoms pre-existing from something else, and hypochondria was resorted to by the mind in a desperate attempt to find a solution to its ailments?

the mind is a powerful thing; have you ever noticed a time when you felt too sick or weak to get up and do anything, but then suddenly winds of fortune blow your way and something you were hoping for happens and you get excited and eager, and coincidentally the feelings of sickness and weakness disappear? the mind is a powerful thing, perhaps.

I believe that out mind has our body store away "reserves" held off specially for when we come across something interesting or pertinent; with drug use however, everything becomes interesting and pertinent, and our body expends those reserved resources such that we no longer have them saved for when we need them. This is why a good portion of drug addiction is psychological; we feel that we can not become interested in anything without the use of drugs.

Yet, if the mind is so powerful, why can't it see past this and fix it? I think it's because we are still imperfect; we are still evolving. The perfect human being, the 'Ubermensch' (in Nietzschean theory), might not feel emotions/pain/pleasure at all, as emotions/pain/pleasure only exist to guide an individual through problems they do not yet know the answer to. The genetically perfect human being would already have all the answers, and therefore have no reason to feel pain/pleasure -- they would behave as automated as an insect.

Imagine if you will a scenario where humanity reaches its technological pinnacle: resources and energy can be created out of thin air, and perhaps human beings will be able to create any reality they want around them at will. In such a hypothetical scenario, wouldn't humanity be afflicted with an unshakable nihilism, as existence would no longer hold meaning or value?

Maybe one day we reach such a pinnacle, and at that point, as we are able to manipulate reality at will, we re-create the dawn of humanity to start it all over again, each human being becoming the god of their own little universe.

Perhaps this is an ongoing process, and we right now are living in an invented reality created by a god, and one day we will become gods ourselves.