off one's meds

prepositional phrase2

1. •
   (informal, figurative) Erratic; out of control.

   • Is he off his meds or something? He's acting crazy.
2. •
   (informal, figurative) Incapable of normal or rational thought.

   • Kanye West took to social media to speak about mental health after a fan claimed that the rapper was “off his meds”. — 2022