I'm having trouble keeping up with some of the words used, but I like the ideas expressed. If you look at evolution per se, then I think it's fairly true to say that the area humans have developed in is the mind. Firstly, (as bipedal humanoids) we grunted and foraged for food every day. Notwithstanding a monolith appearing, and pushing us on our way to self-determination (ie killing each other), if evolution continues, then we will become even less physical and more mental, and ultimately just exist as energetic forces.... (the soul, I hear someone shout!).
So whatif this disease is only countered by those who are sufficiently mentally advanced to overcome it? Look into what the mind can do with hypnotism, and recognising that we (currently) only use 20% of our brain, and you realise the scope for advancement that the human brain has. At my first neurology lecture, the professor started with this statement: "If we had minds simple enough to understand, we'd be so simple, we couldn't"
In order to introduce conflict, whatif some part of your society has found a way to unlock the potential of the human mind so it cures the body of this disease? And then chooses whom to release it to? Naturally another group get wind of it, and capture a scientist, break into a lab, do jedi mind tricks, whatever, to get it? Maybe there's a moral scientist who says "this should be given to the world", and goes on the lam, they try to hunt him down? There could always be a downside to this increase in mental ability, and I'll leave you to think that one up.....if it's meant to be temporary, just to heal the physical ailment, but it's 5,000 times better than heroin, summat like that? I'm sure you'll have better ideas....good luck.