Screen time, reward sensitivity, and mood dysregulation among Egyptian adolescents: concurrent associations and a test of construct distinctiveness

This cross-sectional study examined concurrent associations among self-reported daily screen time, reward sensitivity, and mood dysregulation, and tested whether the two psychological self-report constructs are empirically distinguishable, in a convenience sample of 640 Egyptian adolescents aged 13–19 years. Participants reported typical daily hours in four activity domains and completed six reward-sensitivity items adapted from Behavioral Activation System content and seven mood-dysregulation items modelled on the Affective Reactivity Index. Summed screen time (M = 9.96 h per day, an upper-bound estimate because activities could overlap) correlated with mood dysregulation [ r = 0.53, 95% CI (0.47, 0.58)] and reward sensitivity [ r = 0.63 (0.58, 0.67)]. The two psychological scales, however, correlated r = 0.94; confirmatory factor analyses estimated their latent correlation at 0.997, the heterotrait–monotrait ratio was 0.98, and a one-factor model fitted essentially as well as the two-factor model, so discriminant validity was not supported. In covariate-adjusted hierarchical regression with heteroskedasticity-consistent standard errors, screen time was associated with mood dysregulation [ B = 0.035 (0.024, 0.047), Δ R 2 = 0.017] until reward sensitivity was entered, after which it was not [ B = −0.004 (−0.010, 0.001)]; with the entry order reversed, screen time added Δ R 2 < 0.001 beyond reward sensitivity. Given the measurement overlap, this attenuation is interpreted as the consequence of entering a near-equivalent self-report dimension, not as evidence that reward sensitivity explains mood dysregulation. Demographic covariates, chiefly parental education and school type, which were strongly confounded, accounted for much of the outcome variance. The findings indicate a positive concurrent link in the full sample between reported screen time and a single reward–affective reactivity self-report dimension and underline the need for psychometrically discriminating, multimethod, and longitudinal designs.