Viewing violent news events on social media can cause people to experience symptoms similar to post-traumatic stress disorder (PTSD), scientists warn.
"Social media has enabled violent stories and graphic images to be watched by the public in unedited horrific detail," said Dr Pam Ramsden from the Faculty of Social Sciences, University of Bradford, UK.
"Watching these events and feeling the anguish of those directly experiencing them may impact on our daily lives. In this study we wanted to see if people would experience longer lasting effects such as stress and anxiety, and in some cases post-traumatic stress disorders from viewing these images," Ramsden said.
Some 189 participants (participant's mean age was 37 years old with an almost even gender split) completed clinical assessments for PTSD, a personality questionnaire, a vicarious trauma assessment and a questionnaire concerning different violent news events on social media or the internet.
These included the 9/11 Twin Tower attacks in the US, school shootings and suicide bombings.
Analysis indicated that 22 per cent of participants were significantly affected by the media events.
These individuals scored high on clinical measures of PTSD even though none had previous trauma, were not present at the traumatic events and had only watched them via social media.
Those who reported viewing the events more often were most affected.
"It is quite worrying that nearly a quarter of those who viewed the images scored high on clinical measures of PTSD," said Ramsden.
"There was also an increased risk for those with outgoing, extroverted personalities.
"With increased access to social media and the internet via tablets and smartphones, we need to ensure that people are aware of the risks of viewing these images and that appropriate support is available for those who need it," said Ramsden.
The study was presented at the Annual Conference of the British Psychology Society in Liverpool.
