Would it be possible to create an illness in a dream that becomes part of your subconscious, then manifests itself as symptoms when you’re awake? Probably not, no, but I was thinking about this idea for a story about a dream virus. Imagine if you woke up having brought a dream-created virus with you; no-one would have any immunities to it, so it would spread and spread, and the only time one might be safe is when the mind is in a dream state. So then, there’s a desperate rush as people are put into comas to keep them safe from this virus, maybe to wait until everyone who has the virus has died off.
You could build a whole fictional technology around it; scientists researching how the virus made the transition from concept to reality, then developing other stuff like using the method the virus uses to spread itself through consciousnesses and adapting it into a way to pass thoughts from one mind to another…
… Argh, it’s way too hot today. Calls for an emergency beer + freezer combo!
Oh, on topic, my dream diary on the path to lucid dreaming is going pretty well. I can accurately remember at least one dream per night now, so the obvious next step is ratcheting it up to at least two!