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!
lose (all) one’s marbles
tv. to become crazy. (see also have all one’s marbles.) Have you lost all your marbles?