Introduction The COVID-19 pandemic significantly affected university students' mental health, and loneliness is frequently cited as a key contributor to psychological distress. However, whether loneliness drives distress or distress generates loneliness remains unresolved. This study examined this question during the post-COVID-19 transition, when social opportunities had been restored, but psychological effects may have persisted. Methods A longitudinal web-based survey was conducted with Japanese university students at two time points: October 2022 (T1, during COVID-19 restrictions) and February 2024 (T2, post-restrictions). From 3,000 respondents at T1 and 3,075 at T2, 230 (7.7%; 95 male respondents, 135 female respondents; mean age = 20.3 years) completed both surveys. Cross-lagged regression analysis was used to examine the bidirectional relationships between the Kessler Psychological Distress Scale (K6) and UCLA Loneliness Scale (three-item version) scores. Results Loneliness decreased significantly from T1 to T2 (p = 0.017, d = 0.16), whereas distress did not. K6 scores at T1 predicted loneliness at T2 (β = 0.16, 95% confidence interval (CI) = 0.04, 0.28, p = 0.011), but loneliness at T1 did not predict K6 scores at T2 (β = 0.05, 95% CI = -0.06, 0.16, p = 0.333). An equality constraint test indicated that the difference between the two cross-lagged paths was not statistically significant (Δχ²(1) = 1.26, p = 0.263); therefore, the asymmetric pattern is suggestive of temporal precedence rather than confirmatory evidence of a unidirectional effect. T1 distress also predicted increased passive media consumption at T2; however, T1 behavioral changes did not predict T2 psychological outcomes, except that exercise was associated with lower subsequent distress. Conclusions These findings provide preliminary evidence that, over the 16-month period from October 2022 to February 2024, psychological distress is temporally associated with subsequent loneliness rather than the reverse. In this context, loneliness may partly represent a cognitive manifestation of underlying distress. Interventions for lonely university students would benefit from addressing underlying psychological distress, rather than focusing solely on increasing social connections.
Fujita et al. (Mon,) studied this question.