crazy as a bedbug
mad as a box of frogs
nuts
nut-bar
bats
siao
kee siao
fruity
off one's dot
distraught
daft
up the wall
cracky
bonkers
three stops short of Dagenham
toppy
batty
unglued
funny in the head
out of one's mind
plumb crazy
crazy as a cootie bug
crazy as a cootie
off one's head
bananas
berko
bugfuck
cracked as an egg
hatstand
nutso
off the beam
bughouse
off one's chump
stark raving mad
gone fishing
barking mad
nutzoid
crackers
off one's rocker
off one's onion
becrazed
gobaloon
insano
deranged
off the rails
loony
potty
round the twist
gila
wud
meshuggener
insane in the membrane
loony tunes
not right in the head
stark staring mad
one fry short of a Happy Meal
mad as a meat axe
doolally tap
nutty
not wise
nutballs
doolally
off one's rocket
mad as a March hare
blazing
lunatical
off one's trolley
flip out
demented
loco
mad as a fish
flip
lunatic
darned
fit to kill
off the deep end
infuriated
go to Prestwich
mad as a cut snake
frumious
cuckoo for Cocoa Puffs
round the bend
reality challenged
looney tunes
gobsmacked
mad as a bear with a sore head
in a bake
fuming
ballistic
mad as hops
insanity
steaming
blasted
overfurious
over the edge
insaniac
Ophelian
loopy