Distinct Stress Appraisal Dimensions, Insomnia, and Physical Activity as Differential Pathways to Psychological...

Background: Young adults face a convergence of academic, economic, and social pressures that elevates their risk for stress-related psychological disorders. Perceived stress encompasses two theoretically and empirically distinct components, perceived helplessness and perceived self-efficacy, but most research treats it as a single composite score, obscuring the differential mechanisms through which each dimension influences mental health. Aim: The study aimed to (i) quantify the direct effects of perceived helplessness and perceived self-efficacy on psychological distress, (ii) test insomnia and physical activity as concurrent mediators of each dimension's indirect pathway to distress, and (iii) determine whether the two stress dimensions activate meaningfully distinct mechanisms. Methods: A cross-sectional study enrolled 1688 young adults aged 18-23 years (M = 18.76, SD = 1.01; 41.6% female) from higher education institutions in Tunisia. Participants completed Arabic-validated versions of the Perceived Stress Scale (PSS-10), Insomnia Severity Index (ISI), Depression Anxiety Stress Scales (DASS-21), and the International Physical Activity Questionnaire (IPAQ). Structural equation modeling (SEM) with unweighted least squares estimation and 5000 bootstrap resamples tested direct and indirect pathways. Results: Perceived helplessness exerted strong direct effects on psychological distress (beta = 0.25, p < 0.001) and substantial indirect effects through insomnia (beta = 0.21, p < 0.001) and physical activity (beta = 0.03, p < 0.001). Insomnia was the dominant mediator, showing the strongest bivariate association with distress (r = 0.58, p < 0.01). Perceived self-efficacy produced markedly weaker direct (beta = 0.06, p = 0.002) and indirect effects, a pattern that, like its other associations in the model, runs in the same positive direction as perceived helplessness rather than the inverse direction conventionally expected of a protective factor. Model fit was acceptable (CFI = 0.994, SRMR = 0.018, RMSEA = 0.076, the latter below the conventional 0.08 threshold). Conclusions: Stress management deficits are associated with psychological distress primarily through sleep disruption, consistent with a mediating role for insomnia in this cross-sectional sample. Physical activity provides a meaningful but secondary protective correlate. These findings offer a preliminary, hypothesis-generating basis for stratified, mechanism-based mental health interventions targeting sleep regulation and stress management in young adult populations, pending prospective confirmation.