lose all 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!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
lose (all) one’s marbles
tv. to become crazy. (see also have all one’s marbles.) Have you lost all your marbles?
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.