not have all marbles

not have all (one's) marbles

To not be completely mentally sound or stable. After he started bringing conspiracy theories into the conversation, I started wondering if maybe he didn't have all his marbles. It's easy to feel like you don't have all your marbles when you're that sleep deprived.
See also: all, have, marble, not
Farlex Dictionary of Idioms.

not have all one's marbles

Fig. not to have all one's mental capacities. John acts as if he doesn't have all his marbles. I'm afraid that I don't have all my marbles all the time.
See also: all, have, marble, not
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • not have all (one's) marbles
  • start up with
  • start up with (someone or something)
  • get started on
  • get started on (something)
  • get scabbed
  • scab
  • scabbed
  • peel off from (someone or something)
  • get carried away