What if we had cognitive performance enhancers that were deleterious to your health? Let's say they made you twice as smart but cut your lifespan in half. You might not choose to take them. But others would. And now you find yourself functionally retarded compared to those people. Think about how many advantages they get in hiring and personal success for their Faustian bargain. You might just cave and start doing them yourself. And then say even more powerful ones come along -- these make you four times as smart but are even worse for your body. Everyone just game theoretically spirals into the most extreme Faustian bargains.
That's a dystopian concept I've never seen explored anywhere.
Except sports, where the government steps in and makes sure that doesn't happen. ;)