toys in the attic

(idiomatic) insanity or craziness

Example: 1979, Pink Floyd, album The Wall song The Trial,
  Crazy. Toys in the attic, I am crazy. Truly gone fishing.
1983, Stephen King, Different seasons
  "Loony," Milo said smugly. He'd found the button, all right. "Loony's kid, loony's kid, your father's got toys in the attic, kid, tough break...
1990, Susan Fromberg Schaeffer, Buffalo afternoon
  "You're nuts," Bruno said. "You've got toys in the attic. No one's happy to be here."