Bidirectional Dynamics Between Stress‐Reactive Rumination and Negative Affect: Evidence From a Multimethods Study in Individuals With High Trait Anxiety

<b>Background:</b> Stress-reactive rumination (SR)-the tendency to repetitively think about stressors-has been proposed as a key cognitive mechanism linking trait anxiety to persistent negative affect (NA). However, the dynamic and context-dependent nature of this relationship remains unclear. This study employed a multimethod experimental design to investigate the manifestation of SR in individuals with high trait anxiety (HTA) across different contexts and to examine whether SR and NA demonstrate a bidirectional predictive relationship over time. <b>Methods:</b> A total of 62 participants (31 with high and 31 with low trait anxiety (LTA), respectively) completed a 14-day ecological momentary assessment (EMA) four times/day to record dynamic fluctuations in SR and NA over time in daily life. Afterward, participants underwent the Trier social stress test (TSST) to examine SR and NA responses under acute laboratory stress. Cross-lagged models assessed temporal associations between SR and NA in both contexts. <b>Results:</b> EMA data showed that individuals with HTA reported significantly higher SR and NA than their low anxiety counterparts (<i>p</i> < 0.001). Cross-lagged analyses revealed a significant bidirectional predictive relationship between SR and NA, although this relationship was present only in the HTA group (SR → NA: <i>b</i> = 0.159, <i>p</i> < 0.001; NA → SR: <i>b</i> = 0.072, <i>p</i> = 0.038). In the laboratory, SR and NA were successfully induced by stress, particularly in the HTA group (<i>p</i> < 0.001), but cross-lagged effects were not observed. <b>Conclusions:</b> In individuals with HTA, SR demonstrates both persistence and context-dependent reactivity. The observed reciprocal dynamics between SR and NA in real-life settings underscore the role of attentional control deficits in maintaining emotional dysregulation. Interventions targeting SR may disrupt this maladaptive cycle and reduce anxiety vulnerability.