SAN FRANCISCO (KGO) -- Police have not given a motive, so it's unknown why David Katz shot fellow gamers before killing himself at a Madden video game tournament in Jacksonville, Florida on Sunday.
But, according to divorce filings, Katz's parents said their son had mental health issues and was on anti-psychotic and anti-depression medication at a young age.
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"It didn't surprise me that somebody snapped from the pressure of video gaming," said Dr. David Greenfield, who is a psychiatrist and founder of the Center of Internet Technology and Addiction. He's also an assistant clinical professor of psychiatry at the University of Connecticut School for Medicine.
He spoke to ABC7 via FaceTime on Monday night. "I will tell you, if you're playing at the tournament level or watching people play at the tournament level, it's very easy to get lost in cyberspace and to cross that line online to a level of addiction."
David Katz regularly competed in gaming tournaments with cash prizes. On Sunday, police say he targeted fellow gamers, avoiding other patrons at the bar. One witness said that Katz lost a game the day before the shooting and refused to shake hands afterwards with his competitor.
"If you're a little bit psychologically imbalanced and you have a mental illness or issue and then you lose, I could see why it would push somebody over the edge," said Dr. Greenfield.
But the gaming addiction expert also said, "We are terrible at predicting violence," and adds, "You can't really predict who's going to become violent or not, even if they have a mental health issue because the truth is lots of people have mental health issues and psychological issues and they never commit violence."
Dr. Greenfield says that if you or your child is playing video games more than a few hours a day, is unwilling to get off the game or is using it to alter their mood, it might be wise to look into whether there's a potential problem.
He has created a number of tools and resources, posted on the CITA website, for those struggling with technology related addictions, including a screening test to help determine if you're addicted to video games.
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"There are a lot of families that struggle with kids with mental health issues," said Maryellen Mullin, who is a licensed marriage and family therapist in San Francisco.
According to documents relating to Katz' parent's divorce, David was hospitalized twice as a teenager in psychiatric facilities and struggled with mental health issues and the professional help his mother sought out, since he was at least 11 years old.
Mullin points out that it's very important not to blame parents and that the mental health system isn't always set-up to properly help parents and their kids. "It's very easy to judge what the parents should or shouldn't do, if we're not in that situation."
Mullin says to trust your parental instincts if you're worried about your child. "Your child needs help if they are refusing to talk to you, if they are even refusing to get help and you have a sense that something is wrong."
For more on the developing details of the Madden shooting, visit this page.
Gaming addiction psychiatrist says snapping while playing video game possible