Newsrooms are well-used to handling images of trauma and violence from conflicts around the world, but only recently have journalists and news managers begun to consider the emotional and psychological effects of repeatedly viewing such images.

While the images that are broadcast to the public are often horrific, the raw material that comes into newsrooms unedited is often worse by several orders of magnitude.

In the wake of particularly gruesome images from the school siege in Beslan, and the series of beheading videos from Iraq, the Dart Centre recently drafted guidelines for journalists who deal with these images. Also, the Dart Centre in October held a Frontline Club discussion with several top journalists and managers (click here to read an edited transcript of the discussion).

Several participants in the discussion said that the beheading videos seem to have raised the problem to new levels.

"I was in Rwanda and in the Middle East and various places," said Anthony Massey, foreign duty editor for BBC News. "But the beheading videos in particular seem to come into a new and unique category that none of us have ever experienced before, and caused real trauma to colleagues in the newsroom."

John Clarke of Reuters TV agreed. "As an agency, we've obviously had to deal with disturbing video for many decades, whether that's Rwanda or from Asia or the latest material from Iraq," he said. "So we've had a policy of putting warnings on video for quite a long time." But after the beheading videos began appearing, however, Reuters was asked to extend its normal 10-15 second warning: "We now put a five-minutes' warning on video the first time it's shown, and we try to ring-fence some of this material as well so that it's either run first or last in a feed, so we can give broadcasters the chance to turn off monitors or whatever they need to do to deal with that."

Brian Donald of NBC News said he is concerned about younger members of his staff seeing the videos. "I watch all these disturbing images all the time," he said. "But this hostage beheading is on a totally different level. I'm seasoned, but we've got kids in our office, teenagers, young men and women who are archiving this material and having to watch it and I can't imagine what it's like for them."

But Benedicte Paviot, Anglo-French Journalist with the French Service of the BBC, questioned the notion that the beheading videos represented what some had called "whole new level" of traumatic image, and whether they are really worse than the images from Rwanda. "At the risk of being slightly provocative," he said, "is it that we are we still more shocked by the loss of a white European-American life?"

Gavin Rees of the BBC said that part of what makes the beheading videos more difficult to deal with than other traumatic material is that the beheading videos are meant to serve as propaganda. "If somebody is being beheaded, one of the things that you as a viewer are doing is participating in the perpetrators' sense of power," Rees said. "You know they're getting off on it, and you know it's succeeding because you're watching it. And you're feeling all of those unpleasant feelings associated with it."

» Click here to read an edited transcript of the discussion.