Take Leave Of One's Senses Meaning

(idiomatic) To go crazy; to stop behaving rationally.

Example: 1868, Wilkie Collins, The Moonstone, ch. 1:
  Here I am, with my book and my pencil—the latter not pointed so well as I could wish, but when Christians take leave of their senses, who is to expect that pencils will keep their points?.
1880, Henry Adams, Democracy: An American Novel, ch. 10:
  She plainly said that men seemed to take leave of their senses as soon as women were concerned.
1920, Lucy Maud Montgomery, Further Chronicles of Avonlea, ch. 3:
  "Rachel Spencer, have you taken leave of your senses? What do you mean by such nonsense as this?"
2005 May 8, Nancy Gibbs, "Midlife Crisis? Bring It On!," Time:
  Sue Shellenbarger was 49, living in Oregon and writing her "Work & Family" column for the Wall Street Journal, when in the space of two years she got divorced, lost her father, drained her bank account and developed a taste for wilderness camping and ATV riding that left her crumpled up on an emergency-room gurney. "People around me thought I'd taken leave of my senses," she says.
2007, HRH The Prince of Wales, The Elements of Organic Gardening, Kales Press, page 7:
  One of the great difficulties associated with the adoption of organic or, perhaps more appropriately, sustainable principles at the time I started turned out to be convincing others that you had not taken complete leave of your senses.