Definition
To have impaired mental faculties or to behave in a manner that is not considered normal.
腦袋有問題
He's been talking to himself lately; I think he's not quite right in the head.
他最近一直在自言自語，我覺得他精神有點不正常。
You can't believe anything she says, she's clearly not right in the head.
你不能相信她說的任何話，她顯然精神不正常。
He insists that he can communicate with aliens, the guy must not be right in the head.
他堅持自己可以和外星人溝通，這傢伙肯定精神不正常。