Demi Lovato Fight, Trip to Rehab Tied to Alcohol, Cocaine 1Disney teen queen Demi Lovato led a drug and alcohol-fueled lifestyle that makes Miley Cyrus look like the straight-laced kid she claims to be. A new report claims Lovato was boozing and snorting copious amounts of cocaine before spiraling into rehab.

Lovato, 18, abruptly left the Jonas Brothers tour last week in South America to deal with “emotional and physical” issues, according to her reps. They pointedly said drug abuse was not an issue.

“Demi Lovato left her tour early this weekend in order to seek medical treatment for emotional and physical issues she has dealt with for some time.

“Demi has decided to take personal responsibility for her actions and seek help. She is doing just that. [Demi] regrets not being able to finish her tour, but is looking forward to getting back to work in the near future,” the statement said.

Lovato’s sudden departure was prompted by a fight with dancer Alex “Shorty” Welch, during which Lovato physically assaulted her and left her with a black eye.

Lovato reportedly became enraged when she thought Welch had told tour bosses she had been out late partying.

Now it appears that Lovato’s behavior may have been fueled by excessive alcohol an cocaine use. Life & Style weekly reported this morning that the teen star has been boozing and snorting cocaine long before checking into rehab.

“She was doing line after line like a pro – and she was 17 at the time,” Brian Payne, who partied with Lovato in Texas when she was 17, told Life & Style magazine, on newsstands Wednesday.

“Demi’s been on a tear lately. She’ll chug booze straight from the bottle,” another unnamed source told the magazine.

Payne recalled how the Disney star snorting cocaine during a wild night of partying last December.

“I just remember her doing it [cocaine] as if she had been doing it for a long time,” Payne said. “It didn’t seem like something new to her.”

“Since Joe dumped her, Demi’s been depressed and drinking a lot. It’s been hard for her to keep working so closely with Joe,” another unnamed source said.