Ah, if you're looking for brain research going wrong, you'd probably want to look back... hrm, don't quite remember the distance. 60s, 70s? Somewhere back there. When they were doing lobotomies and electroshock therapy and whatnot -- back when the psych field was actually kinda' monstrous fairly often. There was some pretty terrible stuff.
Thing is, though, even at its worst it wasn't really wide spread -- it is incredibly difficult to actually screw with the brain en masse, even if you're using biological or chemical weapons, even using the best of today's knowledge and, from what I understand, most of the better guesses regarding future capability -- and some of it actually did progress things a bit (we're considerably better at not screwing up brainzapping, ferex). And nowadays we've got considerably stronger methodological constraints on how you go about things, which are mostly pretty well followed.
Basically, from what I understand given my interaction with the psych field (which is, as with you NS, not professional), the risks are not as large as popular fiction or whatnot would like to have one think. Not nonexistent, but the logistics surrounding it makes it unlikely to be an issue. And the benefits are nigh-on immeasurable. As I noted, we really can't afford to stay in a state of ignorance regarding how our brains work -- any damage knowing more could cause is almost certainly outweighed by what not knowing is causing, and would continue to cause.