On Monday, [article id="1651297"]Demi Lovato entered a treatment center[/article] to receive help for what a representative called "emotional and physical issues she has dealt with for some time." Since then, there has been much speculation about what caused her to leave [article id="1651366"]her tour with the Jonas Brothers[/article] and seek help.

People reports that a fight with a touring dancer triggered Lovato's decision to enter the facility, and that problems had been brewing the night before the altercation.

That night was an off night for Lovato, who went out to dinner with her parents, her band and her dancers before spending time with what a source close to the family called a "very small group." The next day, Lovato's stepfather Eddie De La Garza and some tour managers reportedly sat down with that group to discuss the events of the previous evening, when, according to a source close to the situation, Lovato and her friends had been "partying."

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

Lovato reportedly approached the dancer later that day, while the two were on a plane, and accused the dancer of spilling the beans, leading to what the source called "a short, [one-sided] physical altercation."

The family source told People that Lovato later "felt awful about her behavior and realized she needed to take personal responsibility for it," which led to her decision to get treatment. The source said that Lovato was not in drug rehab, but at a treatment center where she can "seek medical care for her physical and emotional issues."

After Lovato entered treatment, rumors circulatedthat "Twilight" star Ashley Greene, who is dating Lovato's ex Joe Jonas, was the cause of Demi's breakdown, but a source denied Greene's involvement, as well as that of Lovato's former tourmates, to People.

"[They] played no role in this," the source said. "They were not involved in the incident," another source added. A rep for Greene had this to say, "There was never an issue between Ashley and Demi, and there is no truth to any rumors about a conflict."

Meanwhile, Lovato's camp has thanked fans for their outpouring of support. "Our entire family appreciates the outpouring of support we have received from Demi's fans, [and] we are touched by their kindness," her mother, Dianna Hart De La Garza, said in a statement.