lose your mind

lose (one's) mind

To become crazy or mentally unsound; to become extremely foolish or foolhardy. I'm going to lose my mind if I have to hear that blasted song once more! I think Jane's grandmother has lost her mind lately. You must have lost your mind if you think that's a good idea!
See also: lose, mind

lose your ˈmind

become mentally ill
See also: lose, mind