Jamie McCarthy / WireImage 1 / 6
Jamie McCarthy / WireImage 1 / 6

By Kat Giantis

Did Demi Lovato decide to check into rehab after she thought someone tattled on her like Cindy Brady on truth serum? People magazine reports the 18-year-old Disney starlet's downward spiral began to pick up speed after an evening out during the Jonas Brothers world tour.

"As she did on most nights off, Demi invited her band, dancers and her parents to dinner," explains a source. "Afterward, she broke off with a very small group."

Word is, that splinter faction received a day-after grilling from Lovato's stepdad, Eddie De La Garza, and the tour managers, who had apparently heard reports that they'd been partying hearty.

"When tour management found out about this, they talked to the people involved, including Demi," explains the spy. "Demi reacted badly and perceived that someone on tour had told on her."

Bad luck, then, that they all had to hop on the same flight that day. The mag says Lovato called out one of the young hoofers for being the suspected snitch, which led to a brief, "one-sided," in-flight "physical altercation."

"Afterwards, Demi felt awful about her behavior and realized she needed to take personal responsibility for it," continues the confidant. "Because of this, and because of the battles Demi has fought throughout her life, both she and her family realized she needed to take steps to get help immediately."

RELATED VIDEO: More on Demi's decision to seek treatment

The teen, whose problems have reportedly included eating disorders, cutting and bullying (not to mention being "forced into showbiz from a young age," according to Us), "decided to seek medical care for her physical and emotional issues at a treatment center," adds the spy. "She is not in drug rehab."

As for whether her ex-boyfriend, Joe Jonas, and his current flame, Ashley Greene, who has been tagging along on the tour, played a part in the incident, that depends on whom you ask.

"On tour [this summer], they were calling her 'Demi Drama,'" a source tells E! News. "After she split with Joe, it was just a whole bunch of drama, very awkward. Everyone tried to be professional, but you could tell it was wearing down Demi. It was a taboo subject to bring up, but clearly she wasn't over Joe."

RELATED: Joe on Demi: 'I really care about her'

Another E! spy claims Lovato "made verbal threats" to the "Twilight" actress during the airplane dust-up, an accusation that insiders and Greene's rep deny.

"There was never an issue between Ashley and Demi," her publicist maintains to People, "and there is no truth to any rumors about a conflict."

Speaking of conflict, Lovato's estranged father, Patrick, is being warned by Disney to shut his piehole after he spoke to RadarOnline about his daughter's issues.

"There are a lot of pressures. That is one of the things I worried about when she signed with Disney," he was quoted as saying. "It's just going to happen."

The comments angered the starlet's inner circle.

"No one speaks for Demi except for her designated representatives," her lawyer fumes to the New York Post. "Unfortunately, several people have taken it upon themselves to speak out -- both on and off the record -- about a situation they know nothing about."

Adds a source, "It's unfortunate [Patrick] chose to speak out in the media because he hasn't played a role in Demi's life for years."

Papa Lovato, for his part, says his words were taken out of context, explaining to the paper, "Demi won't even talk to me. I don't blame Disney; I never said that. I was misquoted. Disney has been wonderful to my daughter. Now their lawyers are warning me not to say anything else."

In 2009, Demi revealed that she hadn't talked to her father in a couple years, sighing, "When somebody lets you down after you've been the only one there for them ... I had to cut off all connection. It was hurting me too much."

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