Britney Spears is still chopping out those people she can't trust in her life - because she fears they'll destroy her.

In a candid MTV documentary, which aired commercial free in America on Sunday night, the pop superstar revealed the events of the past few years have left her mistrusting many of those who have made up her entourage for years - and she's still learning who to trust.

She said, "I've been through a lot this year, actually the last two or three years and my trust has really been battered. I've definitely grown up, big time. I'm very weary of a lot of things. Very protective of myself.

"You are guarded, you have to be that way, otherwise you get taken advantage of and get in situations like I did.

"I had certain people in my life who were just bad people and I was very guarded at first but then I went to a point where I ended up letting them in, because I was lonely... and I really paid the consequences for that."

Spears concluded the often emotionally-charged documentary, which chronicled 60 days in her crazy life from the eve of her 2008 MTV Video Music Awards appearance to the middle of November, by warning those from her past who plan to ruin her future.