mad as a hatter
mad as a mongoose
crazy as a pet coon
toys in the attic
jimjam
round the bend
spunky
unbalanced
balmy
weak-minded
sick-ass
off-minded
misshapen
crazedness
half-cracked
lunatic
lackwit
muddleheadedness
dyspeptic
dementia
few cards shy of a full deck
fucked in the head
crazy
addle-brained
crazen
sardonic
addleheaded
addlepated
off one's box
harebrained
out of one's gourd
out of one's tree
pseudointellectual
rocket
out of one's box
daffy
off one's tree
stunod
knob-end
insane
obtusely
baboon
lunatically
densely
bumbleheaded
half-wit
dottle
toolbox
dumbly
dwaal