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Here’s what smartphones are doing to kids’ brains: our review of The Anxious Generation

We’ve all heard about the negative effects of smartphones on kids and teens. The Anxious Generation lays out the evidence in black and white - then explains how we can reverse the damage.

By Poppy O'Neill | Last updated Aug 1, 2025

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The Anxious Generation by Johnathan Haidt

It’s common knowledge that social media, smartphones and screen time are bad for all of us, and particularly children. They’re diminishing our attention spans, exposing us to online abuse, damaging content and misinformation - but we just can’t seem to look away. 

A whopping 92% of parents on Mumsnet say they’re worried about the effect of smartphones and social media on children’s mental health, with 83% saying they’d support a ban on social media for under-16s. Mumsnet’s Rage Against the Screen Campaign is raising awareness of parents’ concerns in the press and in parliament, and one book brings together not just compelling evidence of the damage being done, but a pathway forward - The Anxious Generation by Jonathan Haidt. 

Haidt deals with the topic of smartphones’ effect on children’s mental health with clarity, avoiding jargon and sticking to the facts. The book begins by carefully laying out the evidence that supports what millions of parents already deeply sense in their own children and in the culture. 

In short, the mental health of under-18s took a steep nosedive between 2010 and 2015, the years smartphones and particularly Instagram took off. This trend has continued throughout the pandemic and beyond. Drawing on sobering graphs like the ones below, Haidt concludes that nothing other than smartphones can explain such a sharp and society-wide change. 

UK Teens (Ages 13-16) self-harm episodes (Source: Cybulski et al 2021, drawing from two databases of anonymised British medical records)

UK Teens (Ages 13-16) self-harm episodes (Source: Cybulski et al 2021, drawing from two databases of anonymised British medical records). Reproduced from ‘The Anxious Generation’, Jonathan Haidt (2024) 

Percent of UK teens depressed as a function of hours per weekday on social media. Teens who are heavy users of social media are more depressed than light users and non-users, and this is especially true for girls. (Source - Millennium Cohort Study)

Percentage of UK teens depressed as a function of hours per weekday on social media. Teens who are heavy users of social media are more depressed than light users and non-users, and this is especially true for girls. (Source - Millennium Cohort Study). Reproduced from ‘The Anxious Generation’, Jonathan Haidt (2024) 

Placing the blame squarely at the feet of the tech companies, Haidt explains how their policies directly affect children’s minds and development. Instagram and TikTok are the most thoroughly taken down, as their video-based feed is the most addictive and damaging for teens - especially girls. Lack of enforcement of age restrictions and policies that actively exploit young minds’ malleability are unflinchingly examined.   

Haidt doesn’t shy away from uncomfortable truths, either. From porn use to social contagion, male sexual predation and the different way social media impacts girls and boys, he explores the extent to which smartphones and social media have changed children’s lives for the worse. 

Plotting the story of children’s mental decline back to the 1990s, when the oldest members of Gen Z were born, Haidt believes the trend towards parents becoming more anxious and allowing their children less freedom exacerbated the effects of smartphones on young minds. He calls this a shift from a ‘play-based’ childhood to a ‘phone-based’ childhood.   

Today’s kids and teens spend less time outside compared to previous generations. This means they take fewer risks - taking risks and dealing with the consequences is what builds resilience. And they’re having fewer and fewer face-to-face conversations, as screens take over their social lives; which means they're missing out on the nonverbal communication and in-the-moment responsiveness that builds social skills and strong relationships. 

Once the reader has taken in all this sobering information, Haidt sets out the practical ways we can reverse this trend and save future generations from a phone-based childhood. He emphasises the importance of collective action and working together in big and small ways. Crucially, the book acknowledges the peer pressure that means kids without smartphones suffer socially when the rest of their class have phones - and advocates for parents teaming up to delay smartphone ownership so no child has to feel alone. And of course, the book includes detailed chapters on the responsibility of schools, governments and tech companies to take action. 

Those of us for whom the genie is already out of the bottle (my kids are 12 and 14 and both have smartphones) aren’t addressed directly, but the chapters on what families can do to create a healthier and more resilient environment for their children are really helpful and full of useful, practical advice on counteracting the effects of smartphone use. 

Time in nature, face-to-face connection, movement and most crucially independence are all things we could do more of, whether our kids already have phones or not. 

I found the way Haidt puts screen-based activities in a hierarchy really useful and actually very comforting - video games come off surprisingly well, for example. It was refreshing to know that there’s so much we can do in our own homes to protect our kids from the harmful aspects of the internet, and encourage them towards healthier activities without the need to move them to a perfect, screen-free bunker.

The Anxious Generation is clear, galvanising and ultimately uplifting. Absolutely essential reading for parents everywhere, no matter how old your kids are. 

About the author

Poppy O'Neill is a Content Editor at Mumsnet and a mother of two. She researches and reviews the products Mumsnetters swear by, with a particular focus on home essentials.

With an MA in Creative Writing and a PGCert in Lifestyle Journalism, Poppy is also a best-selling, award-winning author, with a focus on parenting and children's mental health. Her books have been translated into 12 languages, and in 2023 she won The Week Junior Younger Nonfiction Book of the Year for The Extraordinary Book That Makes you Feel Happy.