Demi Lovato went after Ashley Greene

Demi Lovato checked into rehab earlier this week. A combination of self-image problems and cutting stemming from the verbal bullying she suffered in school all contributed to her decision to go to rehab. The catalyst, however, was a blowup at a South American airport over her ex-Jonas brother boyfriend and his new girlfriend, Ashley Greene.

“She just lost it right at the airport in front of everyone,” says the source. “The [Jonases’] dad basically said right there, ‘That’s it. You’re going home.’ ”

Demi also made verbal threats to Joe’s new squeeze, Ashley Greene, who was at the airport as well and witnessed her meltdown, the source says.

Aside from the cutting, aren’t self-image problems and jealousy the norm for hormonal girls her age? Expecting an 18-year-old to act like a mature adult in Hollywood is like asking a puppy not to pee the carpet. Ashley probably just stood there and laughed at this little chipmunk squeaking at her. Then she stuck her tongue down Joe Jonas’ throat.