loco vs not right in the head

loco

adj
  • Crazy. 

  • Intoxicated by eating locoweed. 

adv
  • A direction in written or printed music to be returning to the proper pitch after having played an octave higher or lower. 

verb
  • To render insane. 

  • To poison with the loco plant; to affect with locoism. 

noun
  • A certain species of Astragalus or Oxytropis, capable of causing locoism. 

  • A locomotive. 

not right in the head

adj
  • crazy, insane 

How often have the words loco and not right in the head occurred in a corpus of books? (source: Google Ngram Viewer )