BT Ket 20a(9) :מידי דהוה אנכסי דבי בר שטיא דבר שטיא זבין ניכסי‏ : it is analogous to the property of the estate of one who is subject to an attack of insanity. One subject to an attack of insanity sold property
See the entire entry for br@šṭy n.m. one subject to insanity attacks