Phone addiction tracks with worse sleep in young adults

Smartphone use has risen globally, and nowhere more intensely than among adults aged 18 to 25, prompting concern about what constant connectivity does to sleep. Sleep is an important predictor of well-being, and problematic smartphone use, marked by an irresistible urge and excessive use, has been implicated in a range of behavioural and psychological disturbances. What has been unclear is how large and how consistent the link with sleep actually is. This review set out to pool the available evidence and put a number on it.

The authors systematically searched SpringerLink, ScienceDirect, PubMed and Google Scholar for observational studies of smartphone addiction and sleep quality in people aged 18 to 25. Screening was assisted by Rayyan AI, and study quality was appraised with the JBI tool. In total, 68 articles were included in the systematic review, of which 63 contributed effect size data to the meta-analysis. Findings were synthesised narratively as well as quantitatively, and publication bias was checked with Egger's regression, Begg's test and trim-and-fill analysis.

The pooled analysis found a moderate positive correlation of r=0.38 (95% CI 0.31 to 0.48) between smartphone addiction and poor sleep quality. The narrative synthesis was consistent: heavier smartphone overuse was linked with delayed sleep onset, shorter sleep, poorer global sleep quality and greater daytime dysfunction. Heterogeneity between studies was very high, at an I2 of 99.25%, meaning results varied substantially across settings. Publication bias tests found no significant evidence that the pooled result was inflated by missing studies.

The authors describe the evidence as strong and consistent, but almost all of it is cross-sectional and based on self-report, so the direction of the relationship cannot be settled: disrupted sleep could drive phone use as easily as the reverse. The review positions problematic smartphone use as a potentially changeable behavioural risk factor for sleep disturbance. It explicitly calls for longitudinal designs, objective measures of both phone use and sleep, and intervention studies to test causality. Until those arrive, the correlation stands, but the mechanism remains open.

If you are in this age group and your sleep is poor, this is a reason to consider whether your relationship with your phone is part of the picture, since the two travel together across dozens of studies. The link is moderate rather than dramatic, and it does not prove that cutting phone use would fix sleep. What it does establish is that problematic smartphone use is one of the more consistent behavioural markers of disturbed sleep in young adults, and one that is at least in principle changeable.