Dynamic within-person associations between problematic social media use and sleep quality among university students: The mediating role of nomophobia and the moderating role of trait rumination.
Gu H, Hu Y, et al. • Applied psychology. Health and well-being • 2026
Within-person increases in problematic social media use were prospectively associated with poorer sleep quality through nomophobia, and this indirect association was more pronounced among university students with higher levels of trait rumination.
Key Findings
Results
At the between-person level, higher problematic social media use (PSMU) was associated with both greater nomophobia and poorer sleep quality among university students.
Study used a 21-day daily diary design with 228 Chinese university students.
Between-person analyses captured stable individual differences in average levels of PSMU, nomophobia, and sleep quality across the study period.
Dynamic structural equation modeling (DSEM) was used to simultaneously estimate between-person and within-person effects.
Results
At the within-person level, day-to-day increases in PSMU were prospectively associated with greater nomophobia, which subsequently predicted poorer sleep quality.
The study employed intensive longitudinal data collected over 21 days to capture short-term dynamic mechanisms.
Nomophobia functioned as a mediator of the within-person association between PSMU and sleep quality.
The prospective design means PSMU on a given day predicted nomophobia, which in turn predicted subsequent sleep quality.
Dynamic structural equation modeling (DSEM) was used to test this within-person indirect association.
Results
Trait rumination moderated the indirect association between PSMU and sleep quality through nomophobia, with the indirect effect being more pronounced among students with higher trait rumination.
Trait rumination was examined as a between-person moderator of the within-person mediation pathway.
The moderated mediation model indicated that individual differences in rumination shaped vulnerability to the PSMU–nomophobia–sleep quality chain.
Students with higher levels of trait rumination showed a stronger indirect association compared to those with lower levels.
This supports a moderated mediation framework integrating both dynamic within-person processes and stable individual difference variables.
Discussion
The study identified nomophobia and trait rumination as potential intervention targets for promoting healthier digital habits and sleep among university students.
Findings highlight nomophobia as a proximal mechanism linking daily PSMU fluctuations to sleep disruption.
Trait rumination was identified as an individual difference factor that amplifies risk.
Authors suggest interventions aimed at reducing nomophobia-related anxiety and addressing ruminative thinking styles.
The study population was 228 Chinese university students followed for 21 days.
Methods
The study used a 21-day daily diary design with 228 Chinese university students to capture dynamic day-to-day associations between PSMU, nomophobia, and sleep quality.
Sample consisted of 228 Chinese university students.
The intensive longitudinal design spanned 21 days of repeated daily assessments.
Dynamic structural equation modeling (DSEM) was employed to handle the multilevel, time-series structure of the data.
The design allowed separation of between-person (stable trait-like) and within-person (day-to-day fluctuation) effects.
What This Means
This research suggests that when university students engage in more problematic social media use on a given day than is typical for them, they tend to experience greater anxiety about being without their phones (nomophobia), which in turn is linked to worse sleep that night. This pattern was observed over 21 days of daily tracking among 228 Chinese university students, allowing researchers to see how these experiences fluctuated together from day to day within the same person, rather than just comparing people to one another.
The study also found that not all students were equally affected. Those who tend to ruminate — that is, who habitually dwell on negative thoughts — showed a stronger chain of effects from social media overuse to phone-separation anxiety to poor sleep. This suggests that a tendency to mentally replay worries or concerns may make some individuals more vulnerable to the sleep-disrupting effects of heavy social media use.
This research matters because it moves beyond simply showing that heavy social media users tend to sleep worse on average, and instead reveals a day-to-day psychological process that may explain why. The findings point to nomophobia and rumination as specific psychological targets that could be addressed in programs aimed at helping young adults develop healthier relationships with their phones and improve their sleep.
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Gu H, Hu Y, Zhong Q, Cheng Y, Fang J. (2026). Dynamic within-person associations between problematic social media use and sleep quality among university students: The mediating role of nomophobia and the moderating role of trait rumination.. Applied psychology. Health and well-being. https://doi.org/10.1111/aphw.70242