School Phone Bans and Adolescent Mental Health in Iceland.

Schoolwide mobile phone bans were not associated with meaningful changes in the primary mental health outcomes of depressive symptoms, anxiety, hostility, or mental well-being between 2018 and 2023.

• Depressive symptoms: β, 0.65 (95% CI, 0.01-1.30).
• Anxiety: β, 0.21 (95% CI, -0.08 to 0.50).
• Hostility: β, 0.23 (95% CI, -0.12 to 0.59).
• Mental well-being: β, -0.52 (95% CI, -1.08 to 0.03).
• The depressive symptoms estimate had a lower confidence bound of 0.01, but the authors judged it not meaningful; the direction was toward slightly more symptoms, not fewer.

Results for secondary outcomes (perceived peer support, screen use, and bullying) were similar, showing no meaningful associations with phone bans.

• Secondary outcomes were perceived peer support, screen use (social media use, gaming alone, gaming with friends, video watching), and bullying (in person and cyberbullying).
• The abstract states that results were similar for the secondary outcomes.

Findings were similar in gender-stratified analyses.

• Analyses were stratified by gender among 23,938 adolescent observations, of which 11,964 (50.0%) were boys.
• No meaningful gender-specific effects of phone bans were reported.

Sensitivity analyses on timing of implementation and more stringent phone restriction criteria were consistent with the main findings.

• Sensitivity analyses examined the timing of ban implementation.
• Analyses also applied more stringent criteria for what counted as a phone restriction.
• Both were consistent with the main null findings.

The study used a nationwide dataset with a difference-in-differences design comparing schools that did and did not implement bans.

• Data came from 70 schools across 3 waves of the Youth in Iceland survey (February 2016, February 2018, November 2023).
• Participants were adolescents aged 13 to 15 years; mean (SD) age was 13.98 (0.82) years; total 23,938 observations.
• Between 2018 and 2023, 22 of 70 schools implemented a phone ban prohibiting student phone use during school hours.
• Analyses were conducted from February 1, 2025, to January 30, 2026.

The authors conclude that school phone bans implemented in isolation may be insufficient to improve adolescent mental health at the population level.

• The conclusion rests on null associations across primary and secondary outcomes.
• The study is repeated cross-sectional, with schools adopting bans non-randomly.