La dégradation cérébrale est-elle réelle - voici ce que disent les experts en santé cérébrale

In 2024, Oxford University Press designated 'brain rot' as its word of the year, defining it as the 'supposed deterioration of a person's mental or intellectual state' caused by overconsumption of, 'trivial or unchallenging" material found on social media and other online platforms.'

"It's what happens when you consume too much low-quality online content, which is like junk food for the brain," says Dr Andreana Benitez, associate professor, department of neurology, Medical University of South Carolina, USA.

But whether that content is actually harming the brain - and how - remains unclear.

Screen habits can shape health

According to research from the Centers for Disease Control and Prevention¹, one half of teenagers in the US spend four hours or more looking at screens each day. Global estimates suggest² adults may be online an average of more than six hours per day. There are no official health guidelines for how many hours of daily screen time are appropriate for teens or adults.

Researchers lack sufficient data to fully understand the concept of brain rot and what it might lead to. "There really isn't a coherent science around it," Benitez says. However, CDC data shows that 1 in 4 teenage frequent scrollers report feeling anxious or depressed.

Some research suggests problems with heavy online use may begin quite young. Adolescents who spend greater amounts of time in front of screens may be more likely to experience mental health issues, including dépression, anxiety, ADHD, and oppositional defiant disorder. They are also more likely to have related physical symptoms such as pain, dizziness, or nausea³.

Other studies have potentially linked brain rot to emotional desensitisation, cognitive overload, negative self-worth, and impaired executive function skills - including memory, planning, and decision-making.

Rethinking our digital diet

While there's no evidence that hours of daily screen time are changing the structure of the human brain, it's what's not happening during those hours that could be harmful, especially for young people whose brains are still developing, according to Dr Costantino Iadecola, director and chair, Feil Family Brain and Mind Research Institute, Weill Cornell Medical Center, New York City, USA.

He says: "The more time young people spend in front of screens, the less time they spend being physically active or having the face-to-face human interactions that supply the developing brain with critical complex sensory and emotional input."

Iadecola says that brain development requires a diversity of exposures: "When you are on your phone, you are not getting these other experiences. We are substituting artificial interactions for human interactions, and artificial interactions lack the complexity of the human experience - the verbal, sensory and emotional reactions we have after interacting with people."

Content matters

It's not just screen time that matters – it's also screen content. Benitez says: "If you consume excessive amounts of low-quality online content, you are more likely to be exposed to information that might distort your perception of reality and harm your mental health," She adds that cycling through large amounts of negative content can also leave you mentally exhausted.

But how much is too much has yet to be determined. Sticking to the junk food analogy, Benitez likens short periods of screen time to the occasional junk food snack. "One bag of crisps might not be that bad, but if you're eating three at a time, that might be a problem," she says.

How to have smarter screen time

Helping kids - and adults - consume a healthier online diet is not easy, Benitez says, because so much of modern life, from schoolwork to shopping, entertainment and socialising, involves online applications.

She says: "With kids, screens are a part of their lives. But, it's incumbent upon adults to curate the content, make sure they are consuming content that's good for them - and in a way that does not result in mental fatigue. We need to make sure they are engaging in critical thinking as they engage with screens."

Benitez also warns children and adults against scrolling before bedtime saying that thought provoking information and being exposed to light when your body should be winding down for sleep might affect your sleep.

The American Academy of Pediatrics⁴ (AAP) suggests families develop screen-time plans together and encourage usage that builds creativity and connections with family and friends. It also suggests parents emphasise the importance of offline activities such as sports, music, art and other hobbies.

The AAP also notes that some screen use may be 'healthy and positive,' a point on which both Benitez and Iadecola agree with. "You could be consuming good content," Benitez says. "There's a value judgment in this." Iadecola suggests making sure online usage is purpose-appropriate. "It's OK to use the technology for whatever task is at hand. The problem is when it becomes addictive behaviour. Everything in moderation." he says.

This article is published with kind permission of the American Heart Association, qui s'efforce de sauver et d'améliorer des vies depuis plus de 100 ans.

1. Center for Disease Control and Prevention: Screen Time Among Teenagers: United States, July 2021–December 2023.

2. Digital 2023 Global Overview Report.

3. Jason M. Nagata, et al: time and mental health: a prospective analysis of the Adolescent Brain Cognitive Development (ABCD) Study.

4. American Academy of Pediatrics: Screen Time and Children.