stoned out of (one's) mind
Severely intoxicated by drugs, especially marijuana. Sorry, I can't remember what we were talking about last night, I was stoned out of my mind. There's no way I'm letting you drive—you're stoned out of your mind!
ˌstoned out of your ˈmind
(slang) not behaving or thinking normally because of the effects of an illegal drug such as marijuana