The singer had been touring South America with her Camp Rock co-stars when an altercation with a back-up dancer on a plane prompted her to seek help for emotional and physical issues.
Lovato told Elle magazine that she had been "completely out of line all summer - just the worst attitude, totally ungrateful".
The teenager also spoke about striking her back-up dancer and friend while on a plane to the tour's next date in Peru, saying: "I just felt like she'd betrayed me,That's the bottom line... When you punch someone on a plane, enough is enough. Right after, I texted my mum and just said, 'I'm sorry'."
However, the former Sonny with a Chance star played down media speculation that her break-up with Joe Jonas had been a major factor in her behaviour: "I wouldn't credit my meltdown to a guy. There was so much other stuff in my life."
Lovato returned to work earlier this year, recently announcing that her third album will be released on September 20, 2011.
"It's definitely more pop, it's not the pop-rock feel anymore," she said in a recent video chat with fans. "I'm showcasing my vocals a lot more like I did on [my new single] 'Skyscraper' and feeling really comfortable with what we have so far."
The untitled album has already spawned lead single 'Skyscraper', which hit number one on iTunes on its release last month. Lovato has also been working on new material with Timbaland at a Miami recording studio.
Lovato will attend this weekend's Teen Choice 2011, where she has been nominated in categories including 'Choice TV Actress - Comedy' for Sonny with a Chance and 'Choice Summer Song' for 'Skyscraper'.
Watch Demi Lovato's video for 'Skyscraper' below: