Associations of perceived stress, sleep quality, and screen time with depressive symptoms among undergraduate health-professional students: a cross-sectional study

Depressive symptoms are common among health-professional students, yet the relative contributions of psychological stress, sleep, and screen exposure remain unclear. We examined these factors and estimated the indirect association between perceived stress and depressive symptoms operating through sleep quality. In a cross-sectional study, 470 undergraduate students in medicine, dentistry, pharmacy, and physiotherapy at a tertiary university in South India completed a self-administered questionnaire. Depressive symptoms (PHQ-9), perceived stress (PSS-4), sleep quality (PSQI), screen time, and physical activity (IPAQ) were assessed. We examined associations using correlation and multivariable linear regression, and estimated the indirect association between perceived stress and depressive symptoms through sleep quality using bootstrapped mediation analysis. The prevalence of depressive symptoms (PHQ-9 ≥ 10) was 19.6% (95% CI 16.2–23.4). Perceived stress (β = 0.43, p < 0.001) and poor sleep quality (β = 0.39, p < 0.001) were the strongest independent correlates of depressive symptoms, while screen time showed only a small independent association (β = 0.11, p = 0.031) and no categorical dose–response relationship. The indirect association through sleep quality was statistically significant, accounting for 12.7% of the total association (indirect effect 0.061, 95% CI 0.023–0.111); this finding persisted after the overlapping sleep item was removed from the depression measure. Perceived stress and poor sleep quality were the correlates strongly associated with depressive symptoms, and sleep quality accounted for a small indirect component of the association. Student mental-health programmes may benefit from attention to both stress management and sleep health.