PARTY TIME
One source who has known the singer since her childhood in the town of Napanee, in Ontario, Canada, tells Star that she appears to be in a downward spiral. "Avril's drinking is getting worse and worse. She's always liked to party but recently all she wants to do is get drunk. And when she gets drunk she wants to fight and cause trouble. She's turning into a nightmare!"

Avril's been candid about her wild ways. In an interview with men's magazine Maxim last year, she boasted: "In a bar a few months ago some chick came up to me and...said something, so I kicked her... and shoved her."

HITTING THE BOTTLE
When it comes to drinking, Avril, who brags about having a fake ID, says, "I'm the kind of girl who, when I go to a bar or club, I just want to get wasted."

And wasted the tiny (5' 3", 103 lbs.) rocker gets. Her drink of choice: a double shot of Grey Goose vodka with ice -- though as this photo shows, the glass and cubes are optional.

A friend tells Star: "Avril totally drinks to get drunk. And when she's drunk anything goes -- she turns into an absolute party animal."

That was evident at Hollywood's chic Spider Club on April 29. The giddy Canadian rocker needed to lean on girlfriends as she stumbled out of the exclusive Moroccan themed hot spot. She signed some autographs before speeding away.

LOSING PALS
Her out-of-control behavior has cost her friendships. According to one insider, Avril fell out with close friend Cliff Sabri, who was also her manager at the time, after they had a disagreement because "he wanted her to stop acting crazy and drinking heavily and concentrate on her music."

Her partying may be taking a toll on her music. One respected rock critic noted that Avril "didn't sound nearly as fresh on her sophomore album, 2004's Under My Skin,"as on her 2002 debut, Let Go.

Avril's wild ways add up to a case of too much too soon, Los Angeles psychologist Robert Butterworth (who's never treated Avril) tells Star. "The price of fame on a young person is usually very high. When you're young and famous, you're used to having money and power and people saying yes all the time, telling you you're great -- and you haven't got the maturity to deal with it. You have nobody to keep you in line and tell you you're messing up or out of control."