In 1972, sociologist and criminologist Stanley Cohen published a book called Folk Devils and Moral Panics, which explored the concept of moral panic: the idea that societies periodically fixate on a newly emerged condition, behaviour, identity or community as being a threat to the public. The fixation is characterized by ‘handwringing’ and calls to action among societal leaders; a particular pattern of media coverage; and experts breaking down the problem and offering diagnoses and solutions.

Today, concerns about the impact of digital and social media on children and adolescents are never far from the headlines, but there is growing evidence that this isn’t simply another case of moral panic. Politicians, religious leaders and others have been speaking out with increasing intensity about how social media harms young people. And a growing volume of scientific literature is exploring the nature and prevalence of those harms, and what might be done about them^1,2.

One thing that differentiates this case from moral panic is that young people themselves are worried, too. “It is not just older generations saying, ‘Kids, get off your screens’,” says Georgia Turner, a neuroscience researcher at the MRC Cognition and Brain Sciences Unit at the University of Cambridge, UK. Work by Turner and her colleagues suggests that nearly half of adolescents think that they are addicted to social media.

“Whether or not they are correct about the use of the clinical terms, they are clearly unhappy with their screen use,” Turner says. “I would say that we should treat people believing that they have a problem as itself a problem or a concern that we need to try and understand.”

Scientists have directed considerable effort into understanding the nature of screen addiction. “We know that the adolescent period is a time of profound changes in how the brain is developing and responding to its social environment, to peers, to family context,” says psychologist and neuroscientist Eva Telzer, co-director of the Winston National Center on Technology Use, Brain, and Psychological Development at the University of North Carolina at Chapel Hill. And now, during that important developmental stage, adolescents are spending more time on digital technology, and in particular on social media.

Concerned about how social media might be affecting children and adolescents, governments around the world are attempting to regulate or curtail its use. Last December, the Australian government implemented a social-media ban for those aged under 16, intended to prevent them from accessing or having accounts on social-media platforms including Facebook, Instagram, TikTok and X. Numerous European countries, including the United Kingdom, France and Italy, are attempting to follow suit.

The situation raises a fundamental question, Telzer says: “How can this social environment potentially be rewiring the developing brain during this really important period when the brain is so sensitive?”

The perfect storm

From birth, the brain grows rapidly in size and connectivity as children learn and develop and neurons proliferate and form connections called synapses. But in early childhood, that growth is accompanied by what’s called synaptic pruning, during which neuronal synapses disconnect and are cleared away. At the end of this process, there are around 40% fewer synapses than at the beginning. Neurons also die in a process called apoptosis. At the same time, the remaining neurons in the brain build up their coat of insulating white matter, or myelin, which is crucial for efficient transmission of electrical impulses.

While synaptic pruning is happening, the adolescent brain is maturing one region at a time, and the order of that maturation doesn’t lend itself to calm and rational thought and behaviour.

The first region to mature is rich in receptors for the hormone oxytocin — which is important in social bonding — and dopamine, a neurotransmitter associated with reward and pleasure. “It’s why every middle-school student wants to talk about who sits where in the cafeteria and who’s more popular than whom,” says Mitch Prinstein, a psychologist at the University of North Carolina at Chapel Hill.

The last brain region to develop is the prefrontal cortex, which is essential for decision-making, exercising judgement and processing emotions such as fear and happiness.

Unfortunately, that makes the adolescent brain vulnerable to some design elements of social media: comparison features such as likes, and addictive elements such as push notifications and endless scrolling. “Imagine in the 80s, there was skywriting across your neighbourhood that said the most popular kid in school is talking about you right now with most of the rest of the grade in your school,” Prinstein says. “You would run down the street looking for them in your neighbourhood — it would be impossible to resist that.”

And that is exactly what social media does for adolescents, he says, describing it as a perfect, tragic storm. “This is what the brain is hypersensitive towards, while not able to stop itself because the prefrontal cortex — the brain’s brakes — are not fully developed until the mid-20s,” Prinstein says.

A big part of the problem is dopamine, a neurotransmitter implicated in a range of addiction disorders. Because of the order in which brain regions mature, adolescents are extremely sensitive and responsive to reward, and social media delivers that in abundance; every like, new follower, positive comment or interesting thing delivers a kick of dopamine, says Turner. We experience those rewards in real life, but at a much lower frequency than on social media.

And that poses a risk to the developing brain. “We do know that if you, for example, do really increase dopamine transmission, that can have massive effects — particularly at young ages – on the way that your brain matures, and then your cognitive control in adulthood, your inhibition, your sensitivity to rewards,” Turner says.

Telzer and a colleague carried out a study involving 79 children and adolescents and found that those who spent more time on their smartphones during school hours — most of it on social media — performed worse on a test that assessed how well they could control their focus and attention. The researchers suggested that the immediate rewards offered by social media could be conditioning adolescents to need constant stimulation, and as a result they find it harder to maintain focus³.

Another study, co-authored by Samson Nivins, a developmental neuroscientist at the Karolinska Institute in Stockholm, which followed more than 8,300 children for four years, found a linear relationship between social-media use and inattention symptoms⁴.

Researchers have also used imaging to look for brain changes associated with social-media use. Nivins and his colleagues used magnetic resonance imaging to look for brain changes linked to using social media, playing video games or watching television over four years in 1,462 participants in the Adolescent Brain Cognitive Development Study⁵. They found that children with higher social-media use showed a small but significant decrease in the volume of the cerebellum, a brain region that is known for coordinating movement and balance and that has a key role in cognition, memory and communication. “Why we are concerned is … the cerebellum is involved in all psychiatric disorders,” Nivins says, suggesting that this could be one mechanism underpinning the association between high social-media use and anxiety and depression.

Social-media-linked disruptions to sleep in adolescents could also affect the formation of insulating myelin, a component of the brain’s white matter, which is crucial for efficient nerve conduction and healthy brain function. Poor sleep is associated with negative effects on the formation and maintenance of myelin. Research involving 976 children in the Adolescent Behavior Cognitive Development Study found an association between shorter sleep, worse white-matter organization, screen time and depressive symptoms in early adolescents. The paper also suggested that sleep duration and its effects on white matter mediated the association between increased social-media use and greater depression-related symptoms⁶. “Social media is the number-one reason why kids are not getting recommended sleep,” Prinstein says.