In recent years, “lying flat” (tang ping) has attracted growing scholarly attention as a passive coping orientation among some young adults, characterized by reduced striving and disengagement from demanding goals. Within this broader phenomenon, an avoidant lying-flat tendency—marked by withdrawal from challenges, low initiative, and preference for short-term relief over effortful coping—may be particularly relevant to university students’ adjustment and technology-related behaviors. In parallel, internet addiction (or problematic, uncontrolled internet use) remains prevalent in college settings and is linked to impaired functioning. Prior work has reported cross-sectional associations between avoidant coping styles and problematic internet use; however, most studies have not adopted longitudinal approaches capable of separating within-person fluctuations (i.e., changes around one’s own typical level over time) from stable between-person differences (i.e., trait-like tendencies). Moreover, potential psychological processes explaining these temporal links—such as self-efficacy as a mechanism and depressive symptoms as a contextual vulnerability—have received limited longitudinal testing within a framework that is sensitive to within-person dynamics.

Using a three-wave design and a random-intercept cross-lagged panel model (RI-CLPM), the study examined: (a) Whether avoidant lying-flat tendency and internet addiction show reciprocal, cross-lagged associations at the within-person level; (b) Whether self-efficacy functions as a time-varying mediator linking the two constructs across adjacent waves; and (c) Whether depressive symptoms moderate the hypothesized within-person pathways. RI-CLPM was selected because it explicitly decomposes observed variance into stable person-specific intercepts and wave-specific within-person deviations, thereby reducing the risk of conflating trait differences with temporal processes.

Participants were undergraduate students from a university in Sichuan Province, China. Data were collected at three time points: March 2024 (T1, n = 739), September 2024 (T2, n = 685), and March 2025 (T3, n = 656). Standardized self-report measures assessed avoidant lying-flat tendency, internet addiction, self-efficacy, and depressive symptoms. RI-CLPM analyses were estimated with robust maximum likelihood (MLR) and full information maximum likelihood (FIML) for missing data. Gender, age, parental education, family income, and concurrent time spent online were controlled to reduce confounding by key sociodemographic factors and internet exposure. Longitudinal indirect effects were tested using bias-corrected bootstrapping. To evaluate moderation, multi-group RI-CLPM analyses compared participants classified into low- versus high-depressive-symptom subgroups.

At the within-person level, cross-lagged paths indicated a significant reciprocal pattern across waves. Specifically, when a student reported higher-than-usual avoidant lying-flat tendency at one time point, the student tended to report increased internet addiction at the subsequent time point. Conversely, above-usual internet addiction also predicted subsequent increases in avoidant lying-flat tendency, suggesting a mutually reinforcing loop. These bidirectional cross-lagged associations remained significant after accounting for stable between-person differences via random intercepts and after controlling for covariates. At the between-person (intercept) level, the random intercepts of avoidant lying-flat tendency, internet addiction, and self-efficacy were correlated in theoretically coherent directions, consistent with the view that individuals with more persistent avoidance tendencies also tend to show more stable problematic internet use and lower enduring self-efficacy.

Mediation analyses further supported self-efficacy as a within-person mechanism. Higher-than-usual avoidant lying-flat tendency predicted subsequent reductions in self-efficacy, which in turn predicted later increases in internet addiction. A parallel indirect pathway was observed in the opposite direction: higher-than-usual internet addiction predicted subsequent decreases in self-efficacy, which then predicted later increases in avoidant lying-flat tendency. These findings suggest that self-efficacy may act as a time-varying psychological “hinge” through which avoidance and problematic internet use perpetuate one another over time. In contrast, multi-group analyses showed no robust evidence that depressive symptoms moderated the key within-person cross-lagged paths, indicating that the reciprocal within-person loop may operate relatively similarly across depression levels in this non-clinical student sample.

Overall, the results provide longitudinal, within-person evidence that avoidant lying-flat tendency and internet addiction are dynamically intertwined and may mutually amplify one another over time, with self-efficacy serving as a central mediating process. The findings align with social cognitive perspectives suggesting that diminished efficacy beliefs can increase reliance on maladaptive coping strategies and short-term relief behaviors. Practically, campus prevention and counseling programs may benefit from targeting self-efficacy enhancement (e.g., mastery experiences, adaptive goal setting, and cognitive-behavioral skill training) to disrupt the avoidance-internet addiction cycle. Future research should replicate these findings across more diverse university contexts, incorporate multi-method assessments (e.g., behavioral logs), and test intervention-based designs to further clarify temporal mechanisms.