Using data from over 500,000 U.S. adolescents, Twenge et al. (2018) documented a significant increase in depressive symptoms, suicide-related outcomes, and actual suicide rates beginning around 2010-2012 — precisely when smartphone ownership crossed 50% among teens.
Key findings:
- 33% increase in major depressive episodes among 12-17 year olds between 2010-2015
- 31% increase in suicide deaths among 15-19 year olds between 2010-2015
- The increase was particularly pronounced among girls
- Adolescents who spent 5+ hours daily on electronic devices were 66% more likely to have at least one suicide risk factor
The AI Connection
While this study focused on smartphones and social media, it establishes the baseline for understanding how ubiquitous digital technology affects developing brains. As AI systems become the primary interface for digital interaction (AI chatbots, AI-powered social feeds, AI companions), these findings become even more relevant.
Controversy
This research has been debated. Orben & Przybylski (2019) argued the effect sizes were small ("no worse than eating potatoes"). However, the population-level trends in suicide rates are difficult to dismiss.
Source
Twenge, J. M. et al. (2018). Increases in Depressive Symptoms, Suicide-Related Outcomes, and Suicide Rates Among U.S. Adolescents. Clinical Psychological Science, 6(1), 3-17.