unhinged

adjective3

1. •
   Not furnished with a hinge.
2. •
   (figurative) Mentally ill or unstable; deranged; insane.

   • The revolution of 1830 and the discomforts of his private life so preyed upon his mind that his reason became unhinged, and he had to be removed to an asylum near Caen, where he died in 1834. — 1876
3. •
   Not having ever been mounted using a stamp hinge.