The more people watch, listen or scroll through hours of news coverage of events such as terrorist attacks, the more likely they are to develop stress symptoms that in turn increase their media consumption during the next mass violence event, according to a nationwide study.

The analysis was published April 17 in the journal Science Advances, the week of the six-year anniversary of the 2013 Boston Marathon bombing, which killed three people and injured more than 260.

The researchers surveyed more than 4,000 Americans over three years, after the Boston bombing and through the time of the 2016 Orlando Pulse nightclub mass shooting, where 49 people died and 58 people were injured.

Study participants who reported increased media exposure following the Boston bombing were more likely to experience stress symptoms — such as intrusive thoughts about the event, feeling numb and feeling hypervigilant or irritated — six months later, according to University of California, Irvine psychology professor Roxane Silver and her colleagues.

People who experienced the symptoms were more likely to be worried about future events two years after the bombings, and to increase their media consumption about the Pulse nightclub shootings when they occurred one year later.

Trauma-related media coverage can lead to a cycle of high distress and high media use, the researchers concluded. The team did not diagnose individuals in the study with clinical disorders such as posttraumatic stress disorder.

Silver's lab has been studying the impact of media consumption of violent events on stress symptoms for nearly 20 years, since the September 11, 2001 terrorist attacks in New York, Washington, D.C. and Pennsylvania.

Their research consistently shows "that increased media consumption is associated with increased symptoms of distress, but this is the first opportunity we've had to examine this question as it relates to different events over time," said Rebecca Thompson, co-author of the study and a postdoctoral researcher in Silver's lab.

Participants in the study consumed an average of six to seven hours of coverage of each violent event. The more they consumed, the more likely they were to develop the stress symptoms that led to the cycle of increased worry and media consumption. This study does not pinpoint a specific number of hours of media exposure after which symptoms would appear, said Silver.

The study also does not address whether certain types of media — television reports versus newspaper stories — are more likely than others to trigger stress symptoms. In a 2016 study of the Boston bombings, Silver and her colleagues found that people who watched more television and viewed more news online were more likely to be exposed to graphic content such as disturbing images and sounds.

Media organizations can reduce the potentially stressful impacts of their coverage by focusing less on the "sensationalistic aspects" of a mass violent event — such as showing graphic images of injuries — and more on informational accounts of the events, the researchers recommend in their paper.

Moderation is the key for media consumers, said Thompson. "Obviously when these events occur, people want to be informed about what's going on, and the media is a really great tool for that, but it becomes an issue when people are consumed by it and can't step away from it."

Silver said she is no longer surprised to see such a strong connection between media consumption and stress after these events. "But the media landscape has changed dramatically since 2001," she said. "Now people are exposed to images and sounds and stories through a variety of sources, and these kinds of questions become far more important with the constant access to this content."

[Credit for associated image: Anubis Abyss/ Flickr]