Jurors were warned weeks in advance that they were coming and that they’d be hard to watch, but the videos played at the Luka Magnotta murder trial this week and last still came as a shock to some in the Montreal courtroom, and the scenes of dismemberment, macabre sex acts and violent death they showed could end up taking their toll.

"Just viewing the trauma can produce post-traumatic stress disorder (PTSD) in exactly the same way as if you were actually part of it," said Ken Welburn, clinical director of the Ottawa Anxiety and Trauma Clinic.

'You're seeing somebody suffering that desperately needs help, and you can't do anything.' - Ken Welburn, clinical psychologist

Watching more than a dozen videos of Magnotta repeatedly stabbing Concordia University student Jun Lin with a screwdriver, cutting his throat and dismembering and defiling his corpse brought jurors face to face with the crime, and it's that proximity, along with the severity of the violent acts themselves, that can have negative psychological effects.

"You're seeing somebody suffering that desperately needs help, and you can't do anything. You're just sitting there watching it," said Welburn, who has studied PTSD symptoms in people who watched the 9/11 terrorist attacks unfold on TV. "The helplessness is a big predictor of getting PTSD."

It was that feeling of helplessness that contributed to the PTSD suffered by renowned forensic psychiatrist John Bradford in 2010 after he had to view videos of former Canadian Air Force colonel Russell Williams raping, torturing and killing Jessica Lloyd and Marie-France Comeau. The videos were considered so disturbing that they were never shown at Williams's murder trial and were seen only by a handful of lawyers and experts.

Jessica Lloyd-Russell Williams-Luka Magnotta

Videos showing the rape and murder of Jessica Lloyd, above, and Marie-France Comeau were so graphic and disturbing that they were never shown at the trial of their killer, Russell Williams. (Handout/Canadian Press)

For Bradford, who has worked some of Canada's biggest murder trials, they brought back similarly shocking scenes from videos he had to watch for the 1995 trial of serial killer Paul Bernardo.

"I had this video show going on and on, and I couldn't sleep," Bradford said in a 2013 interview with the Ottawa Citizen in which he described gradually becoming more and more agitated, depressed and even suicidal in the weeks and months after viewing the Williams tapes.

Bradford, who turned down the Magnotta case because of his PTSD, was not the first to remind us that it's not only victims' families and laypeople who sit on juries who are at risk of being traumatized by disturbing evidence.

Luka Magnotta trial

Journalists, shown here questioning Crown prosecutors Helene Di Salvo, left, and Louis Bouthillier, are also at risk of suffering PTSD-like symptoms after viewing disturbing video and other evidence presented at trial. (Paul Chiasson/Canadian Press)

Retired Ontario Superior Court justice Patrick LeSage was so traumatized by the videos of rape and torture he saw while presiding over the Bernardo trial that he wasn't "physically and mentally able" to conduct Bernardo's dangerous offender hearing, he told the Globe and Mail in 2002.

In 2010, Ontario court Judge Stephen J. Hunter refused to watch a video of a father repeatedly raping his 13-year-old daughter, saying he had seen enough such examples in his career to be able to hand down a sentence without viewing it.

Remember why you're watching, psychiatrist says

Welburn said jurors at the Magnotta trial have to remind themselves why they're watching the disturbing videos: to help ensure a fair verdict and perform a valuable service for the community.

However, he added, they must pay attention to how the content is affecting them and not become numb or dissociated.

"You have to be able to say, ‘We're feeling it. Can we take a break?' so you have some control over how much you're immersed in the trauma, so you're not just sitting there helplessly," Welburn said.

Paul Hunter remembers well the effect that horrific evidence can have on those in the courtroom. The CBC correspondent covered the Bernardo trial, which, he said in an interview conducted over email, "overflowed with unthinkable horror."

Patrick Lesage-Luka Magnotta-trial

Patrick LeSage was the presiding judge at the Paul Bernardo murder trial in 1995 and has spoken publicly about the traumatic effect that the graphic video evidence presented in court had on him. (John Woods/Canadian Press)

In that trial, journalists and family members were spared from seeing the worst of the video evidence, which was shown to the judge, jurors and attorneys on TV screens turned away from the public, but still heard the audio and read vivid transcripts of what was on the videos.

"We sat and we listened, day after day, to the sound of a 15-year-old girl being repeatedly raped by two monsters," Hunter said of a video showing Bernardo and his accomplice girlfriend Karla Homolka raping and torturing Leslie Mahaffy, the first of four rape videos played in court.

"Then we sat through the same process with Kristen [French] and Jane Doe, as we had likewise with Tammy [Homolka]. With every victim, lawyers would play 'key' moments again and again and again. It was numbing."

Most jurors will get over it

Hunter says details from the trial still pop into his mind occasionally and certain songs will forever be associated with the radio soundtrack that played in the background of some of the rape videos — the same way that New Order's True Faith might become an unwelcome reminder for those who heard the song played in the edited Magnotta video shown last Thursday.

To this day, Hunter won't shoot any home videos because the format reminds him of the home movies and sex tape made by Bernardo and Homolka, which were among the videos played in the view of the whole courtroom.

Diran Lin -Luka Magnotta

As traumatic as disturbing evidence is for jurors, it is unimaginably more devastating for family members like Diran Lin, above, who has heard and seen explicit details of his son's murder laid out in court. (Christinne Muschi/Reuters)

Psychologists say most people are able to get the violent acts they see and hear described in court out of their heads within a few weeks because humans are hardwired to subconsciously suppress such information or file it away as an aberration.

"It's really the exception that they cannot cope with it over the long term," said psychologist Stéphane Guay, co-director of the Trauma Studies Centre at the Institut universitaire en santé mentale de Montréal.

If memories persist, it could be a sign that individuals are suffering some of the same PTSD symptoms that soldiers or victims of a violent attack experience.

'Having recurrent, distressing memories or dreams — this is the most frequent signal that something is going wrong.' - Stéphane Guay, psychologist

"Having recurrent, distressing memories or dreams — this is the most frequent signal that something is going wrong," Guay said.

Other signs of PTSD or acute stress include depression; increased substance abuse; feeling wired, anxious or irritable; having trouble sleeping and concentrating.

"Those kind of symptoms, for a lot of people, happen in the first two days to four weeks, but for most people, it'll wash out without getting treatment. It just kind of fades," Welburn said.

Avoidant or obsessive behaviour should raise alarm

A sign that someone is not coping well with what they saw at trial is if they avoid talking and thinking about it altogether and become reclusive and withdrawn. Conversely, becoming obsessive and not wanting to talk about anything else is also cause for alarm, Welburn said.

People exposed to the details of violent crimes can also become hypervigilant, developing suspicions about strangers or beefing up their security.

"People will generalize what they saw in the trial to daily life," Guay said. "They expect this will happen in their neighbourhood."

In most provinces, jurors who find they're having trouble coping can ask the court to cover the cost of psychiatric counselling. The extent of jury support varies by province. In Quebec, jurors are entitled to five one-hour therapy sessions at a maximum cost of $65 an hour, while British Columbia and Manitoba provide jurors with a group debriefing session with a trauma expert after the trial.

Leslie Mahaffy-Luka Magnotta trial

Jurors in the trial of Paul Bernardo had to watch videotapes showing the rape and torture of 15-year-old Leslie Mahaffy and several of Bernardo's other victims. (Handout/Canadian Press)

There are things jurors can do on their own to cope during and after the trial, Welburn said.

"Trauma and anxiety is all about arousal [of the nervous system] ... so anything you can do to get into a relaxed state is good," he said. That could be connecting with friends and family or doing activities you enjoy.

People who have a high capacity to feel empathy or who are strong visualizers, especially, should develop strategies for keeping haunting thoughts at bay.

"Bring up some positive or pleasant images and direct your mind there rather than to the trauma," Welburn said. "When you leave the courtroom and the door closes — visualize the door closing, the TV going off and say to yourself, ‘That's done now' ... and bring up the image of [a beach in] the Caribbean."

Guay says imagining in detail what you are going to see on a graphic video before it is played in court can help minimize the shock of the actual images.

Repeated exposure to horror weighs on the psyche

Journalists and lawyers have their own coping strategies.

Hunter had three rules he stuck to while covering the Bernardo trial: no black humour, make the victims part of every story and get away — mentally and physically — from the court during lunch breaks.

"Those three 'rules' helped me cope with the rest of the abhorrent sights and sounds of each day," he said.

'I find that some things, and sometimes even minor bits of sadness, weigh upon me as they never would before.' - Lee Burgess, Crown prosecutor

For Crown prosecutor Lee Burgess, who viewed the same videos Bradford did while working the Williams trial, having close relationship with colleagues who see the same type of evidence he sees provides "a great level of support."

Burgess has prosecuted many heinous crimes in his close to 25-year career and says that while he has built up a certain immunity in order to do his job, there is a definite cumulative effect on one's psyche.

"I find that some things, and sometimes even minor bits of sadness, weigh upon me as they never would before," he said. "Images and thoughts of disturbing events, of victims and of their families will now frequently enter my thoughts in ways they would not have when I had little exposure to such difficult cases."