Longitudinal dyadic associations between psychological stress and sadness rumination in young and middle-aged stroke patients and their spouses: an actor-partner interdependence model study.

AIM: To explore the longitudinal associations between psychological stress and sadness rumination in young and middle-aged stroke patients and their spouses based on the actor-partner interdependence model. METHODS: The convenience sampling method was used to select 256 stroke patients and their spouses as the participants. The Stanford Acute Stress Reaction Questionnaire and the Rumination on Sadness Scale were used to investigate the patients at the acute stage (T1), 3 months (T2), and 6 months (T3) after stroke. Equivalence testing and cross-lag analysis of the actor-partner interdependence model were used for statistical analysis. RESULT: 256 dyads (512 individuals) were enrolled; 230 dyads (460 individuals, 89.8% retention) completed all three waves after excluding 26 dyads due to stroke recurrence (n = 5), death (n = 2), and loss to follow-up (n = 19). The results of the equivalence test showed that the psychological stress and sadness rumination of patients and their spouses met the Configural Invariance, Metric Invariance, and Scalar Invariance across time (∆CFI ≤ 0.01). Actor effects: patient stress→subsequent rumination (β = 0.24, 95% CI [0.18, 0.30], p < 0.001; β = 0.20, 95% CI [0.14, 0.26], p < 0.001); spouse stress→subsequent rumination (β = 0.21, 95% CI [0.15, 0.27], p < 0.001; β = 0.18, 95% CI [0.12, 0.24], p < 0.001). Partner effects: spouse rumination→patient rumination (β = 0.17, 95% CI [0.10, 0.24], p < 0.01; β = 0.15, 95% CI [0.08, 0.22], p < 0.01). CONCLUSION: Young and middle-aged stroke patients and their spouses exhibited high temporal stability in psychological stress and sadness rumination, with significant bidirectional actor effects and asymmetric partner effects. Longitudinal associations indicated a significant positive spillover effect, wherein spouses' sadness rumination prospectively predicted patients' sadness rumination. LIMITATIONS: Single-center recruitment, unmeasured confounders (rehabilitation intensity, medication adherence), no gender-stratified partner-effect test.