guilty crown code geass well okay the mc's there are not really insane, but some shit happens which turns it a bit dark but well from your picture it seems you know code geass^^
Hellsing Ultimate - Alucard is kinda crazy Drifters - Made by same as hellsing Higurashi - pretty dark and all characters crazy at certain points Monster - different kind of dark... one of the characters is crazy not necessarily the MC tho Mirai Nikki - Yuno is pretty crazy Shin sekai Yori - dystopia anime School days - some crazy bitches in here Paranoia Agent - Plot revolves around a crazy person Re zero: dark and MC does turn crazy at points
Dark .. but not really insane .. hmm but then again if you go by our societies standards then everybody is insane there .. Ghost in the Shell ... perhaps also Ergo Proxy Oh and Trigun further shameless edit Kurozuka