This randomized clinical trial, conducted entirely online, enrolled 1012 US teenagers and young adults aged 13 to 29 years. The study aimed to evaluate how different warning messages about social media harms influence perceived effectiveness for discouraging social media use and awareness of those harms. Participants were exposed to 13 distinct health warnings covering various harms, such as negative body image and depression and anxiety, along with a screen time break warning and a neutral control message. The primary outcome was perceived message effectiveness for discouraging social media use, and a key secondary outcome was awareness of the harms of social media. Follow-up duration was not reported, and the study phase was not specified.
All health warnings and the screen time break warning were perceived as more effective than the neutral control message for discouraging social media use. The average differential effects (ADEs) ranged from 0.32 (95% CI, 0.24 to 0.41) to 0.62 (95% CI, 0.53 to 0.71), indicating a consistent advantage over the control. When compared directly with the screen time break warning, all health warnings were perceived as more effective, except for the health warning about addiction. The ADEs for these comparisons ranged from 0.16 (95% CI, 0.08 to 0.24) to 0.30 (95% CI, 0.22 to 0.37), while the addiction warning showed a smaller, non-significant effect of 0.07 (95% CI, -0.004 to 0.14).
For the secondary outcome of awareness of the harms of social media, all warnings were perceived as increasing awareness more than the control message, with ADEs ranging from 0.19 (95% CI, 0.10 to 0.28) to 0.63 (95% CI, 0.54 to 0.72). Furthermore, all health warnings were perceived as increasing awareness more than the screen time break warning, with ADEs ranging from 0.21 (95% CI, 0.13 to 0.28) to 0.44 (95% CI, 0.36 to 0.52). These results suggest that specific health warnings, particularly those addressing mental health harms like depression and anxiety, may be more impactful than generic screen time reminders.
Safety and tolerability data were not reported in this trial, which is expected given that the intervention involved exposure to warning messages rather than a therapeutic agent. No adverse events, serious adverse events, or discontinuations were documented. The absence of such data is not a concern for this type of behavioral intervention, but it does limit the ability to assess any potential psychological distress that might arise from viewing alarming warnings.
These findings align with prior research on health warning labels, such as those on tobacco products, which have been shown to increase risk perceptions and reduce intentions to use. However, this study is novel in applying that framework to social media use among a younger demographic. The results extend prior coverage that has examined correlates of anxiety and depression (e.g., heart rate variability and psychobiotic interventions) by suggesting a potential population-level messaging strategy to address social media's impact on mental health. Yet, unlike clinical interventions that directly target symptoms, this study focuses on perceived message effectiveness, which is a precursor to behavior change but not a guarantee of it.
Methodological limitations include the lack of reported follow-up, which prevents assessment of whether the perceived effectiveness translates into sustained changes in social media use. The study also did not report limitations or funding sources, and the reliance on self-reported perceived effectiveness rather than objective measures of behavior is a key constraint. Additionally, the online setting may introduce selection bias, as participants were self-selected internet users. The study did not measure actual reductions in social media use or clinical outcomes such as depression or anxiety scores, so the clinical relevance remains indirect.
For clinicians, these results suggest that requiring health warnings on social media platforms could increase awareness of harms and discourage use among teenagers and young adults. This could be a valuable public health intervention, particularly given the high prevalence of mental health concerns in this age group. However, clinicians should interpret these findings cautiously, as perceived effectiveness does not equate to real-world behavior change. The study provides a rationale for policymakers to consider such warnings, but further research is needed to evaluate their impact on actual usage patterns and mental health outcomes.
Several questions remain unanswered. Future studies should measure actual social media use behavior over time, assess whether warnings reduce symptoms of depression and anxiety, and determine the optimal content and frequency of warnings. Additionally, research should explore potential unintended consequences, such as desensitization or increased anxiety from repeated exposure to alarming messages. Comparative effectiveness against other interventions, such as digital literacy programs or parental controls, would also be valuable. Until such evidence is available, clinicians should view these findings as an early step toward evidence-based social media regulation, not as a proven clinical strategy.
How this fits prior evidence
This randomized trial extends prior coverage by directly testing a messaging intervention for social media use, a modifiable factor linked to depression and anxiety. It complements earlier findings on physiological correlates (e.g., heart rate variability) and nutritional approaches by offering a scalable public health strategy. The results confirm that health warnings are perceived as effective, but they do not measure actual behavior change, leaving a gap that future research must address.
