What we know
U.S. youth self-reported persistent sadness rose across the 2010s and peaked in the 2021 YRBS. Autism surveillance prevalence among 8-year-olds has risen for two decades. Parent-reported ADHD diagnosis is higher than in the early 2000s.
Diagnostic trends
A rising line is a question
Where reliable published series exist, we show them. We do not imply that increasing prevalence proves social-media causation. Alternative explanations sit beside every chart.
How we know it
Public surveillance systems and surveys. These are not exposure studies.
What else could explain it
Recognition, stigma, criteria, access, demography, distress, clinical practice, pandemic disruption, and—possibly—social media. Several can be true.
What we don't know yet
The share of any trend attributable to digital environments after those alternatives are modelled.
CDC Youth Risk Behavior Survey (published reports). Unit: %.
Self-report of feeling sad or hopeless almost every day for two weeks or more. Not a depression diagnosis. 2021 is a pandemic-year survey.
Alternative explanations
- Genuine increase in distress
- Reduced stigma and greater willingness to endorse items
- Smartphone / social-media cohort effects (hypothesized, not proven by this series)
- COVID-19 disruption around 2021
- Changes in survey mode or school participation
CDC Autism and Developmental Disabilities Monitoring Network. Unit: per 1,000.
Surveillance prevalence among 8-year-olds, not a social-media exposure study. Diagnostic criteria, awareness, services, and ascertainment all changed across this period.
Alternative explanations
- Broadened criteria and diagnostic substitution
- Improved recognition, including in previously missed groups
- Service incentives for diagnosis
- True increase in incidence (possible, not isolated by these data)
- Social-media identification (not measured by ADDM)
CDC / National Survey of Children’s Health published estimates. Unit: %.
Parent-reported lifetime diagnosis, not a validated clinical interview series and not a measure of TikTok self-diagnosis in adolescents. Points are rounded from published CDC summaries.
Alternative explanations
- Improved recognition, including in girls
- Changes in survey wording and sampling
- Educational and clinical practice changes
- Possible over-identification at boundaries
- Social-media content (not identified in these surveys)
Trends we do not fake with a chart
Specialist reports of tic-like presentations and clinician impressions of DID-related referrals are important and are treated in case studies. They are not national time series with a public denominator, so they are not drawn here as if they were. Eating-disorder service pressure during COVID is documented in several countries; we would rather cite services research than invent a comparable line.