gila
funny in the head
berko
bugfuck
round the bend
one fry short of a Happy Meal
meshugge
cracky
up the wall
batty
daft
siao
bonkers
three stops short of Dagenham
toppy
fruity
kee siao
bats
nut-bar
doolally tap
off one's dot
distraught
nuts
bananas
mad as a box of frogs
spitting mad
screwy
doolally
crazy as a bedbug
cuckoo for Cocoa Puffs
meshuggener
not right in the head
gobaloon
loony tunes
yampy
flip out
round the twist
wud
insane in the membrane
flip
off the beam
off one's onion
nutzoid
nutty
gone fishing
off one's rocker
dement
out of one's tree
détraqué
headbanger