Destoni says that at age 3 or 4, she started becoming angry.

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“When I get mad, I only mean to take it to, like, an argument, but then it gets into punching, hitting, knocking my head into things,” the now 14-year-old says.

The teen admits that she chased her younger sister’s babysitter with a butcher knife because they were “kind of annoying” her. She also says her behavior has gotten her in trouble at school, and that she’s been kicked out of every school she’s attended.

WATCH: Mom Says Teen Is Violent, Acts Out, Tells Her To 'Shut The Hell Up'

“I’ve threatened to shoot someone. That’s one of the things I’ve gotten in trouble for at school, three, four times,” she says.

Destoni’s mom, Melissa, says she’s so concerned about her daughter’s out-of-control behavior, she wrote to Dr. Phil for help.

In the video above, see what happens when Destoni grows irritated answering questions from a Dr. Phil producer. And, hear what Dr. Phil says to the teen.

On Monday’s episode, Destoni’s mother and grandmother share more about the teen’s behavior. And Dr. Phil drills down to determine what may be driving it. Plus, on Tuesday, Destoni comes face to face with a group of her peers. See what happens when Dr. Phil offers her help. Check here to see where you can watch.

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14-Year-Old Admits To Chasing Her Sister With Butcher Knife