bananas
batty
daft
nut-bar
three stops short of Dagenham
toppy
up the wall
cracky
nuts
becrazed
nutso
off one's chump
bughouse
hatstand
crackers
doolally tap
out of one's mind
off one's head
funny in the head
not right in the head
meshuggener
mad as a box of frogs
fruity
kee siao
plumb crazy
bonkers
crazy as a cootie bug
siao
crazy as a cootie
nerts
cuckoo for Cocoa Puffs
off one's onion
off one's rocker
insane in the membrane
loony tunes
gone fishing
nutzoid
off the beam
berko
mad as a March hare
crazy as a bedbug
meshugge
nutballs
gobaloon
bats
bugfuck
distraught
off one's dot
reality challenged
gila
jimjam
nutty
doolally
bananapants
wackadoo
demented
lose one's mind
looney tunes
loopy
potty
off the rails
deranged
loony
nucking futs
insano
cracked as an egg
crazypants
jiggy
wiggy
banoodles
buggish
loco
bammy
cray
loced out
cray-cray
gaga
nutbar
tapped
unglued
one fry short of a Happy Meal
round the bend
lunatic
flooey
cooked
half-cracked
lunatical
crazy-ass
mad
flip out
flip
screwy
go potty
off one's rocket
détraqué
get one's freak on
mad as a fish
insanity
semimadness
looney-tunes