"I'm Ready This Time": Investigating physiological and emotional habituation to repetitive social stress.

Background: Repetitive stress is at the nexus of acute and chronic stress, and there is limited knowledge about how physiological and emotional responses change with repeated exposure.

Purpose: We examined stress-related biomarkers and emotional responses to repeated social stressors, and we tested behavioral moderators.

Methods: In Study 1, 42 adults completed the Trier Social Stress Test (TSST) twice, 4 months apart. Serum inflammatory cytokines (interleukin-6 [IL-6], tumor necrosis factor-α [TNF-α]), blood pressure, pulse, salivary cortisol, and state-level anxiety were measured surrounding the stressor. In Study 2, 84 married individuals completed two 20-minute discussions of contentious topics in the marriage, 1 month apart. Serum IL-6, TNF-α, blood pressure, pulse, salivary cortisol, and state affect were collected surrounding the conflict. Trained experimenters rated positive and negative behavior during the conflict.

Results: In the repetitive Trier paradigm, participants reported less anxiety (Ps = .048) and had higher anticipatory IL-6 responses (P = .014) at Visit 2, compared to Visit 1. In the repetitive marital conflict paradigm, participants had lower positive affect (P = .0004), as well as systolic blood pressure (SBP) (P = .009), diastolic blood pressure (P = .0003), and pulse (P = .027) habituation at the second visit. Objectively rated negative conflict behavior interacted with visit to predict TNF-α (P = .025) and SBP (P = .037) responses. Positive conflict behavior did not moderate outcomes (Ps > .06).

Conclusions: Stress-sensitive systems can habituate or sensitize to even nontraumatic, repetitive social stressors. Patterns of habituation or sensitization may vary by time between repetition, type of social stressor, stress-sensitive system, and participant behavior.