The We Can't Stop hitmaker - who recently shocked fans with her racy performance at the MTV Video Music Awards last weekend - admitted she has "issues" and struggles taking much-needed breaks from work.
Speaking to the Sunday People newspaper, she said: "I'm messed up... I have so many fucking issues."
"I am so fucked up - everyone does dumb stuff when they are messed up."
"I don't have a normal life. I take a hiatus every now and again but I'm not good at that."
The 20-year-old star rose to fame with the lead role in Hannah Montana - but she claimed she was never like the clean-cut character she portrayed on the Disney Channel show.
She explained: "During Hannah Montana I think people knew I was acting. I've never been able to hide anything, a bit like Justin Bieber.
"Others who have been on kids' shows try to act like their characters - but I'm not like that."
"I never pretended I was as good as the Disney Channel writes... You will be amazed at some of the notes I got... It's crazy. But they can't make people not grow up."