Insane, brainsick, psychotic, bat****, delusional, crackpot, lunatic, buggy, touched, deranged, nuts, nutcase, bananas, wacko, wacky, cuckoo, fruitcake, fruity, fruit loops, mad, crackers, batty, balmy, loony, potty, crazed, bonkers, daffy, daft, screwy, warped, disturbed, half-baked, unbalanced, sick, unhinged, demented, bizarre, dingbat, ding-a-ling, wierdo, kook, screwball, wacky, dippy, gaga, loco, out to lunch, crazy as a loon, having a screw loose, having bats in one's belfry, having lost one's marbles, around the bend, crazy as a coot, not all there, not right in one's head, off one's dot, off one's rocker, on the dark side of the moon, off one's onion, out of (or off) one's head, out of one's mind, touched in the head, mad as a fruitcake, mad as a hatter, looney-tunes, lost one's marbles, not playing with a full deck, soft in the head, not all there.