Justin Bieber’s neighbors aren’t happy: Complaints about the teenage multi-millionaire pop star range from speeding through the neighborhood to spitting in someone’s face to, most recently, egging a nearby house.

Whatever the current investigation turns up, Bieber is certainly not the first example of a child star misbehaving, but it raises the question: Why do child stars so often fall apart?

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Several factors probably come into play, experts said, including personality, a unique upbringing, and an early sense of entitlement.

Frank Farley, a former president of the American Psychological Association who studies risk taking, has a name for the type of personality often shared by celebrities: T-type, or thrill-seeking.

“It’s what gets them to where they are,” he said. “They’re pushing the envelope, they’re taking risks. Going to a casting call and being judged -- most people couldn’t tolerate it. One of the top 10 fears in America is speaking in public.”

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Type T personalities are often highly creative, people who can handle uncertainty and risk. It would be hard to make it in Hollywood without those qualities. But there can be a downside.

“The other side is the T-negative,” Farley said. “It’s the destructive risk-taking, thrill-seeking. Take John Belushi and Chris Farley -- you have to be really creative to be an improvisational comedian. But then in their makeup they had the destructive side and that’s what killed them (both died of drug overdoses at age 33). Let’s hope Justin doesn’t go in that destructive direction.”

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Often Type T personalities are able to overcome that destructive side by using their creativity and innovative qualities.

“They’ll say, I can find my way out of this mess,” Farley said.

Child stars tend to face different hurdles than most of us, pointed out Karen Sternheimer, author of "Celebrity Culture and the American Dream: Stardom and Social Mobility" and director of undergraduate studies in the Department of Sociology at the University of Southern California.

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“For many people in this circumstance, the power dynamic between them and traditional authorities can be reversed, especially if the child is supporting their family financially,” she said.

Child celebrities often miss out on institutional experiences like school that provide a common background for most people. They grow up with greater autonomy and fewer constraints than most kids. Combine that with early success, and child stars may “come to see themselves as special, as they are treated like deities by fans and some around them,” Sternheimer said.

Those early experiences may lead them to believe that rules don’t apply for them, or that they won’t face the same consequences as others.

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One consequence child celebrities face more than most, however, is the scrutiny of everything they do, living so much of their lives in the public eye.

“These stories serve as modern-day morality tales reflecting a cultural tension between consumption and self-control,” Sternheimer said.

“(In my book) I write that such stories can be connected to the Horatio Alger rags-to-riches stories of the 19th century, which emphasized hard work and moral turpitude as necessary for economic success. Stories of out-of-control celebrities -- especially young ones -- highlight failures of self-control.”