If you're old enough to remember the September 11 attacks in 2001, then you may still see the events in your mind – even though more than two decades have passed.
Even if you didn't see the attacks live, television networks brought the horrific footage of the planes slamming into the World Trade Center in New York to people across the globe.
And it was seen over and over.
Some people watching repeat broadcasts developed symptoms of post-traumatic stress disorder (PTSD), including nightmares and flashbacks.
Fast forward to the age of social media and smartphones, and our exposure to distressing content has never been more intense.
Loading...WARNING: Some people may find the themes discussed in this article distressing.
In recent months, for example, a flood of stories of those affected by Middle East conflict — including shocking images of dead or injured children — have circulated on X (formerly Twitter) and other platforms.
Experts fear people spend too much time on their phones, scrolling through news and social posts that makes them feel sad, anxious or angry.
And they say such "doomscrolling" could insidiously increase our risk of "vicarious trauma". So what can you do about it?
What is vicarious trauma?
Vicarious trauma is "second-hand" trauma, experienced when you're not directly impacted by a distressing event, but you see it happen or are repeatedly exposed to stories of it.
Initially studies of this phenomenon focused on professions like soldiers, police, psychologists or journalists who had contact with cases involving graphic cases of violence or abuse.
But since events such as September 11, more attention has been paid to the impact of repeated exposure to distressing events via the media.
"People were concerned about the [television] networks, particularly in America, repeatedly showing the planes going into the towers," says Richard Bryant, a psychologist and expert in PTSD who works at UNSW Sydney.
Cases of PTSD documented in research after September 11 showed symptoms increased with the amount of time people spent re-watching the horror footage.
Professor Bryant says repeated exposure to the coverage at the time were particularly distressing for children and young people.
"For very young children, they honestly believed there were new attacks every time they saw it."
Kim Felmingham, chair of clinical psychology at the University of Melbourne, agrees.
"You just could not really escape the footage, and it was going over and over again," she says.
The never-ending flow of traumatic content on social media from events today, such as the Israel-Gaza conflict, might have an even worse effect.
"The concerning thing is it's really unregulated," Professor Felmingham says.
"Certainly, with the level of the saturation, the level of the violence that's being displayed … and I think the level of vitriol in the debate… I think all of that likely is going to be leading to vicarious trauma for some people."
Arash Javanbakht is a psychiatrist and neuroscientist at Wayne State University in Detroit Michigan where he directs the Stress, Trauma, and Anxiety Research Clinic.
He points to uncensored videos featuring traumatic images of decapitated children as an example of the extreme content circulating on social media.
"What you see on TV is a lot more filtered and cleaned up," Dr Javanbakht says.
"You never see a decapitated child on the TV, but you go on Twitter or you go on other social media you may see that.
"The intensity of exposure to the goriness and the horrific aspects [of conflict] is much higher."
The good, the bad, and the ugly of scrolling
Prominent images of injured or killed children take a particular psychological toll, Professor Felmingham says.
Research involving police and paramedics shows that when a child is involved in a traumatic incident, or in footage they watch, the risk of developing PTSD is compounded.
And the fact that traumatic images are interspersed in the same feed as everyday life make matters worse, Professor Felmingham adds.
"What can really enhance horror is when you're seeing those juxtapositions."
Dr Javanbakht agrees, emphasising the context of distressing content matters.
When we sit down on our couch and turn on the TV news, we have time to prepare ourselves to be confronted by distressing imagery.
"But with social media, there is a kind of uninvited … unpredictable nature," he says.
"You're scrolling, you see pictures of puppies, you see your friend's wedding, and then boom, you see those most horrible images of atrocities."
In this context, he says, the brain goes into "threat detection mode".
"When we see these images frequently, the threat and fear … can redirect attention to seeking more of them, and then the algorithms perceive us as interested in them, and keep showing us more of these."
Professor Bryant says many people re-expose themselves to distressing material about conflicts such as the Israel-Gaza war, because it can trigger anger, which helps reaffirm a world view in which one side has done wrong.
"This becomes the focus of the person's waking hours, which is psychologically not healthy," he says.
Not everyone is affected by vicarious trauma
While there is some research linking social media exposure with vicarious trauma, it can be hard to prove a causal link, not least because there's the "chicken and the egg" problem: Do people get stressed from doomscrolling, or do we doomscroll because we're stressed?
But experts say there's enough evidence to suggest it can be a problem in the same way as other second-hand exposures to trauma have been shown to be.
The good news, though, is that vicarious trauma is not something that affects everyone.
"Most people watching burnt or killed children will be distressed, but that stress is typically short lived," Professor Bryant says.
And even if someone does develop PTSD symptoms vicariously, the risk of this is less than developing them through direct exposure to trauma.
"But we do know that that depends a bit just on the intensity and the extent of what people are being exposed to," Professor Bryant adds.
And, he adds, repeated distress happening multiple times a day can have a cumulative effect on a person, with re-exposure consolidating memories in a more distressing way each time.
The fact that the Israel-Gaza conflict is still occurring after many months adds to the problem of repeated exposure.
How do you protect yourself?
So how do you know if you're seeing more distressing images on social media than is good for you? What are the signs of vicarious trauma?
Dr Javanbakht says while it's normal to feel terrible about distressing events and images, it shouldn't take over your whole life.
"If I'm starting to not be able to function at work, function in my interpersonal relationships … that is a basically a red flag," he says.
Dr Javanbakht says signs to look out for include:
- constantly thinking about the information you've seen
- feeling depressed beyond some sadness that comes and goes when you are exposed to the information
- having nightmares.
He recommends people ask themselves why they are viewing this content.
"What's the purpose? [Do] I want to know? Or [do] I want to get angry because emotions have energy?"
He says while "disaster voyeurism" can be driven by a feeling of guilt that we could be doing more to help victims we are witnessing, overexposure can risk desensitising yourself.
"Person number 1,000 [becomes] just a statistic … The stress might still be there, but on the surface [you] don't feel it."
There is balance, he says.
"I'm not saying anybody should stop knowing about the world. We should know, but we should know what to know, how to know, and what's the use of it.
"Going through that video 10 times is not going to help the person who suffered in that video."
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