...are things we don't want to actually come true. In Mindkiller, Spider Robinson talks about "wireheading" as the new drug - using electrodes to directly stimulate the brain to induce pleasure.
Wireheading requires brain implants - and somehow every time anyone comes up with a way to do it without, they show up dead.
Except now a company called Thync is claiming that they're working on "a wearable device designed to directly perk up or calm down the brain" (Xconomy).
There's no proof the device exists or works, but with recent developments in machine-mediated telepathy, it might. And it wouldn't require implants.
Fortunately or unfortunately, it already seems to have been decided that the FDA has some jurisdiction...
(Edit: My husband also pointed out that we just saw this kind of technology used to mess people up...in an old episode of The Man From U.N.C.L.E.)