12/11/2013 08:19 am ET Updated Jan 25, 2014

Stress Symptoms Linked With Increased Viewing Of Boston Bombing Media Coverage

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When a tragedy occurs, such as last year's Newtown shooting or the bombing at the Boston Marathon, it's easy to get lost for hours on end in the 24-7 news coverage. But according to a new study, immersing yourself for a prolonged period of time in media coverage of distressing and tragic events could be bad for your mental health.

Researchers from the University of California, Irvine, found an association between acute stress symptoms and watching six or more hours a day of news coverage of the Boston Marathon bombing the week after it occurred.

The association seems to hold true especially for people who have previously experienced a traumatic event, people with a lifetime history of being exposed to traumatic events, and people with a pre-existing mental health condition.

"We suspect that there's something about repeated exposure to violent images or sounds that keeps traumatic events alive and can prolong the stress response in vulnerable people," study researcher E. Alison Holman, an associate professor of nursing at the university, said in a statement. "There is mounting evidence that live and video images of traumatic events can trigger flashbacks and encourage fear conditioning. If repeatedly viewing traumatic images reactivates fear or threat responses in the brain and promotes rumination, there could be serious health consequences."

More than 4,500 adults answered surveys in the two to four weeks after the 2013 Boston Marathon that analyzed their direct and/or indirect exposure to the bombing and media coverage of the bombing. They were also asked whether they had experienced trauma previously in their lives.

Researchers found an association between watching six or more hours a day of media coverage about the bombing, and being nine times more likely to report high acute stress symptoms -- such as hypervigilance, intrusive thoughts, feeling detached and going out of your way to not see a reminder of the incident -- compared with people who watched less than an hour every day.

The new findings are published in the journal Proceedings of the National Academy of Sciences.

The concept that watching distressing news can lead to stress is not new. The National Center for PTSD points out, for instance, that after 9/11, people who watched more television media coverage of the terrorist attacks experienced more stress symptoms than those who watched less of the TV coverage. Similarly, children who watched more news about the Oklahoma City bombing experienced more symptoms similar to PTSD.