Why would a child murder his parents?

Recently, 15-year-old Nicholas Browning confessed to killing his entire family in their Baltimore home. According to reports, he used his father's 9mm gun to execute his mother, father, and two younger brothers (ages 14 and 11) while they slept, then returned to a friend's home to play Xbox after ditching the gun in the woods.

Nick confessed to the killings after telling police he was angry with his father for lecturing him and removing his car privileges for one week.

To his community, Nick Browning seemed like a cheerful well-adjusted boy. He played on his high school's varsity golf team, was a Boy Scout leader, and honors student who played the cello.

Although shocking, this isn't the first time children have murdered their parents:

Just this week, a 12-year-old boy killed his mother in their Douglas, Ariz., home after having a dispute over household chores. The boy's name isn't released yet, but he will possibly face first-degree murder charges.

In the 80s, there was the famous case of the Menendez brothers who plotted and carried out the murder of their parents, after agreeing their father was abusive to their mother. They reasoned if they killed their father, they'd have to kill their mother so she wouldn't turn them in.

Jacob Brighton, 16, killed his parents because he felt like a "disappointment." He told police he shot his dad three times in the back, then shot his mother while she ran away. Brighton faces a possible sentence of life in prison if convicted.

Matthew Hackney, a 17-year-old who was sent home from school for being drunk, shot his parents and grandmother to death, then died in a car crash. Matthew, who had never been in trouble before, was reportedly scared he'd get disciplined for failing a drug test.

Sarah Johnson, 18, shot her parents to death when she was 16 years old in their Idaho home. She was reportedly angry with her parents for disapproving of her boyfriend.

What is happening to children?

"Murdering one's parents is a very specific type of rage," says Jane Greer, Ph.D., a family therapist in New York City. "You're literally cutting off your lifeline, the people who brought you into this world. It usually stems from feelings of retaliation, resentment, and animosity."

"Sometimes, one incident can cause a kid to snap but there's usually a build-up of events," she says. "Teens say 'I hate you, I wish you were dead!' but to act on their fantasies, you're then dealing with someone who has no impulse control."

What's more, she adds, often times after killing one parent, the teen panics and tries to cover their tracks. "It's common for someone to murder the rest of their family after killing one member," she says. "The thinking is, 'If I kill everyone, there will be no one to turn me in.'

Greer says as children enter their teens, they haven't fully developed the ability to reign in bad behavior. But that's not to say every parent should worry--in fact, most shouldn't because these cases are rare. Being sullen, snappy, and disconnected from the family are characteristics of every kid in America. So how do you know when you really have a problem?

"Most parents believe their kid would never harm them, but the victims also thought that too," Greer says. "Parents believe their children are loyal to them, but by encouraging your kid to be open about his social life, he'll be less likely to behave secretively and vulnerable to outside influences."

"This issue hasn't been studied enough to form a profile for a teen killer, but we do know that kids who disconnect with their parents, have no impulse control and anger issues are more susceptible to killing," she says. "Trust your gut and get your kid counseling if you're concerned."