2 - (SYM 26) Stress Reactivity and Risk Appraisal Mediate the Association Between Major Depressive Disorder and Generalized Anxiety Disorder Symptoms over 18 Years

Stress reactivity (SR) is the psychological response to perceived demands during stressful situations. Stress risk appraisal (RA) evaluates how disruptive an event is to essential life domains like work and relationships. SR captures emotional responses to stressful events; RA reflects cognitive appraisal of potential disruption. Though trait-like, SR and RA may fluctuate daily. The variability and mean of SR and RA in daily stressors may clarify stress-appraisal processes contributing to long-term heterotypic continuity of symptom severity from MDD to GAD. Context-dependent propensities in appraising and responding to daily hassles may inform long-term cognitive-behavioral therapy monitoring. We explored how mean and standard deviation of SR and RA mediated the longitudinal association between MDD and GAD symptom severity.

The analytical sample included 735 participants (39.86% female, 60.14% male; 94.97% White) from the Midlife Development in the United States database with at least 3/7 days of Wave 2 Daily Diary data and completed Wave 1 and Wave 3 Composite International Diagnostic Interview-Short Form data. We ran two structural equation mediation models with latent predictor and outcome variables: (1) W1 MDD severity predicting W3 GAD severity; (2) W1 GAD severity predicting W3 MDD severity. Following MIDUS conventions, SR was computed as daily sum of stressor severity and stressor-related negative affect. RA was operationalized as daily composite of 49 domain-specific stress-risk appraisal items. For each participant, mean and SD of SR and RA were calculated across post-random-forest-imputation daily diary entries. Each model contained one W2 mediator at a time. Autoregressive paths controlled for baseline outcome levels.

We found directional asymmetry: significant indirect effects emerged only for W1 MDD-to-W3 GAD severity, not the reverse. Only higher W2 SR mean and SD showed significant indirect effects (Cohen's d=0.243–0.244, p≤.031). SR dynamics accounted for approximately 31–44% of the W1 MDD-W3 GAD association, whereas RA accounted for approximately 14%. Higher mean levels and fluctuations of SR were associated with more severe GAD symptoms approximately 18 years after W1.

SR, but not RA, dynamics may index risk-relevant stress-reactivity processes in daily life, contributing to heterotypic continuity from MDD to GAD. These findings may inform sustainable, long-term CBT monitoring strategies accounting for individual and contextual differences in stress-reactivity patterns.