insane vs round the bend

insane

adj
  • Used by or relating to insane people. 

  • Causing insanity or madness. 

  • Extremely good; incredibly amazing. 

  • Characterized by insanity or the utmost folly; ridiculous; impractical. 

  • Exhibiting unsoundness or disorder of mind; not sane; utterly mad. 

round the bend

prep
  • Crazy, mad or insane. 

  • Close to or in close proximity to another location. 

How often have the words insane and round the bend occurred in a corpus of books? (source: Google Ngram Viewer )