also: どうかしてる
expression
something's wrong; not right in the head; crazy
Used to say someone is acting strangely, not themselves, or seems mentally off. Often said with concern or mild criticism. Can range from light teasing to serious worry.
彼は今日どうかしている。ずっと黙っている。
He's not himself today. He's been silent the whole time.
そんなこと言うなんて、どうかしてるよ。
Saying something like that, you must be crazy.