The pop star is back on a career high after a series of legal hassles and publicity lows, and he admits he opted to bounce back after a string of heartaches and disappointments led to him making bad choices in life.

"I was really in a weird place," he tells U.S. news show Access Hollywood. "I was in the industry so young and you have so many people that you lean on and trust... I just didn't have my guard up, so I got my heart broken a bunch of times by friends (and) people in the industry. After a while I was like, 'You know what, I'm not gonna open up to people anymore; I'm just gonna be guarded'.

"I was really about myself for a while and then it just got to a point where I was, like, so unhappy, I was so lonely, I felt so alone. I was so closed off to everyone, even my friends. I was like, 'I can't trust anybody', so I started just acting out, doing whatever I wanted to do."

Bieber's personal lows led to a real songwriting struggle.

"When you're in kind of a bad headspace, you're writing about being in that bad headspace," the What Do You Mean? singer adds. "It just really doesn't really match up with what I'm doing now, so we scrapped a lot of songs and we've moved in a pretty different direction."