Mental Health
The evidence is extensive, contested in detail, and clear in direction. Here is what is established, what is genuinely uncertain, and what Facebook knew.
How to read this page. Tap any underlined word to see the precise academic term and a short definition. Expand any "Deeper" box for the evidence and contested points. The main text works on its own — you can skip both and still get the whole argument.
What is well-established
Adolescents who spend more than three hours per day on social media are significantly more likely to experience poor mental health outcomes. The effects are consistently worse for girls than boys. Passive scrolling — consumption without active social interaction — correlates more strongly with negative outcomes than active social use. These findings appear across multiple large studies in the US, UK, and internationally, and have achieved near-consensus among researchers.
Passive use
Consuming a feed without interacting — scrolling, watching, reading, but not posting or messaging. Studies distinguish it from active use (conversation, sharing with people you know). Passive use is the form most consistently linked to lower mood, plausibly because it is mostly upward social comparison with none of the connection that makes social contact restorative.
Sources
- Verduyn, P. et al. (2015), Passive Facebook usage undermines affective well-being, Journal of Experimental Psychology: General 144(2).
The timing matters. Adolescent mental health in the US, UK, and other high-income countries began deteriorating around 2012 — which corresponds with the period when smartphone ownership crossed 50% and social media became the dominant leisure activity for teenagers. Jonathan Haidt's synthesis of this evidence in The Anxious Generation (2024) documents the convergence across data sources and countries.
What Facebook knew
In 2021, Frances Haugen disclosed internal Facebook research documents to the Wall Street Journal and to Congress. The documents showed that Facebook's own researchers had found that Instagram makes body image issues worse for one in three teenage girls. A 2019 internal study found that among teenagers who reported suicidal ideation, 13% in the UK traced the desire to kill themselves to Instagram. The company knew. The product continued.
The Haugen documents are primary source evidence — not the allegation of a critic but the company's own research conclusions. They show internal debate about whether to act on these findings and internal decisions to prioritise growth.
The debate: Haidt vs Orben
The scientific debate on causality is genuine. Amy Orben and Andrew Przybylski at the Oxford Internet Institute have published influential critiques arguing that the effect sizes in most studies are small and that the correlational evidence does not establish causation. Their 2019 paper found that social media's effect on wellbeing was comparable in magnitude to wearing glasses or eating potatoes.
Effect size
A measure of how big a relationship is, separate from whether it is statistically real. Much of the dispute turns on this: a finding can be highly statistically significant (very unlikely to be chance) and still small in practical terms. Whether social media's measured effect on adolescent wellbeing is "small" or "meaningful at population scale" is a genuine disagreement about how to weigh the same numbers.
Sources
- Orben, A. & Przybylski, A.K. (2019), The association between adolescent well-being and digital technology use, Nature Human Behaviour.
Jonathan Haidt and Jean Twenge argue these critiques understate the evidence and that the methodological choices Orben and Przybylski made minimised effect sizes. The dispute is ongoing in the academic literature.
The honest position, which this site holds: correlation between heavy social media use and worse mental health outcomes is established across multiple studies. Causality is contested. The direction of the evidence is clear enough to act on, particularly given what the internal platform documents show about knowledge of harm.
Why "not addiction, design"
Framing heavy social media use as "addiction" is both inaccurate and counterproductive. A 2025 study in Scientific Reports found that framing social media overuse as addiction — rather than as a response to deliberate design — reduces users' sense of agency and increases helplessness. The accurate framing is: the product was designed to be this compelling. That reframe preserves the user's capacity to respond.
How we know — why the correlation is solid but causation stays contested
Most of the evidence is cross-sectional: it measures social media use and wellbeing at one moment and finds them associated. That cannot tell you the direction — whether the feed worsens mood, or low mood drives more scrolling, or a third factor drives both. This is the core of Orben and Przybylski's critique. Their widely-cited analysis used a "specification curve," running thousands of defensible model variants to show the average measured association is small and sensitive to analytic choices.
What would settle it, and why it's hard. Stronger designs — large longitudinal cohorts that follow the same children for years, and randomised reductions in use — are underway but slow, and randomising children's social media for long periods is ethically and practically fraught. So the debate persists honestly.
Why we still say "act on it." Two things tip the balance without resolving the academic question: the timing evidence across countries (Haidt's synthesis), and the Haugen documents — Facebook's own researchers finding harm to teenage girls. Internal knowledge of harm is a different kind of evidence from a contested effect size, and it is what moves this from "interesting correlation" to "grounds for action."
Sources
- Haidt, J. (2024), The Anxious Generation, Penguin Press.
- The Facebook Files — Frances Haugen's internal disclosures, Wall Street Journal and US Congress, 2021.
- Orben, A. & Przybylski, A.K. (2019), The association between adolescent well-being and digital technology use, Nature Human Behaviour.
- Verduyn, P. et al. (2015), Passive Facebook usage undermines affective well-being, Journal of Experimental Psychology: General 144(2).
- Anderson, I.A. & Wood, W. (2025), Overestimates of social media addiction are common but costly, Scientific Reports.