lose one's marbles

lose (one's) marbles

To be or become mentally deficient, incompetent, or deranged; to become of unsound mind. My poor grandmother started losing her marbles after she had a stroke. I've been so sleep deprived lately that it feels like I've lost my marbles!
See also: lose, marble
Farlex Dictionary of Idioms.

lose one's marbles

see under have all one's buttons.
See also: lose, marble
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • lose all one’s marbles
  • lose marbles
  • lose one’s marbles
  • lose (one's) marbles
  • lose your marbles
  • lose one's buttons
  • lose (one's) buttons
  • lose one's mind
  • lose your mind
  • lose (one's) mind