go potty
lose one's mind
go mad
go ham
jimjam
not have both oars in the water
drive someone crazy
get one's freak on
take leave of one's senses
insanity
loco
loony tunes
off the beam
lose it
insane in the membrane
off one's rocker
gone fishing
nutzoid
off one's onion
becraze
craziness
dumb out
pop one's cork
crack up
meshuggener
not right in the head
madden
derange
bughouse
hatstand
cuckoo for Cocoa Puffs
off one's chump
nutso
insaniac
crackers
hystericize
mad
off one's head
out of one's mind
cracked as an egg
go bananas
fruitloop
psycho
lunatical
cooked
go moggy
flip
lunatize
gobaloon
nut job