His aunt's not right in the head, poor soul - you sometimes see her wandering up the street in her nightie.
(redirected from be right in the head)
be not right in the head
To be mentally unwell or unstable. The term can be used both literally and hyperbolically. Tim has been behaving very erratically lately, so I'm afraid that he's not right in the head.Oh, Liz is not right in the head if she thinks that plan will work!