Physiological Markers of Interpersonal Stress Generation in Depression.

Abnormalities in parasympathetic nervous system activity have been linked to depression, but less is known about processes underlying this relationship. The present study evaluated resting and stress-reactive respiratory sinus arrhythmia (RSA) to a laboratory stressor as predictors of daily interpersonal stress generation and depressive symptoms, whether stress generation mediated the relationship between RSA and depressive symptoms, and potential sex differences. A sample of formerly depressed 102 emerging adults (18-22 years; 78% female) completed a laboratory stressor and daily assessments of stressors and depressive symptoms over two weeks. Multilevel modeling revealed that: 1) lower resting RSA predicted daily depressive symptoms; 2) less RSA reactivity predicted interpersonal stress generation, 3) interpersonal dependent stressors mediated the relationship between RSA reactivity and daily depressive symptoms, and 4) sex differences occurred in the resting RSA-depression relationship. These findings highlight the importance of resting RSA and RSA reactivity in the examination of depression and interpersonal processes.