Justin Bieber admits he had a drug problem

In the latest episode of JUSTIN BIEBER's YouTube series, he discusses his history with drugs.

He says that he first smoked weed when he was 12 or 13,and eventually became"really dependent"on it.

Justin also says, quote, "There was a time when I was sipping lean, popping pills, doing Molly, shrooms, everything."

It was SERIOUS. He says, quote, "My security would come into my room at night to check my pulse. People don't know how serious it got. It was legit crazy scary . . .

"I was waking up in the morning and the first thing I was doing was popping pills and smoking a blunt and starting my day."

(There's UNCENSORED profanity in the episode.)