Patients with borderline personality disorder show initially reduced psychophysiological relaxation levels but intact relaxation response

Borderline Personality Disorder (BPD) is associated with psychological as well as physiological dysregulation in patients, including reduced parasympathetic activity at baseline and difficulties returning to baseline after a stressor. Whether this impacts the relaxation response independent of a stressor has so far not been investigated. In a within-subject design, we compared two relaxation interventions, a virtual reality nature video, and a paced breathing intervention. We assessed a female-only sample, with 20 BPD patients (mean age = 23.75 ± 4.39) during their inpatient treatment and 22 matched healthy controls (HC; mean age = 22.68 ± 2.68). Psychological relaxation was assessed with the Relaxation State Questionnaire (RSQ) and physiological relaxation with vagally mediated heart rate variability (HRV). We employed multilevel models to test whether BPD significantly influenced the psychophysiological relaxation response. For psychological relaxation, we found an increase in RSQ scores in both groups in response to both interventions. The HC showed overall higher RSQ scores. For physiological relaxation, we found overall higher HRV values in the HC group but no differences in the relaxation response. BPD patients exhibit lower psychophysiological relaxation levels at baseline and throughout the experiment, while there was no significant difference in response to relaxation interventions when compared to HC. Future studies should focus on interventions targeting baseline psychophysiological relaxation in BPD patients. • Breathing exercise increases physiological and subjective relaxation. • Virtual reality nature video increases only subjective relaxation. • Reduced baseline psychophysiological relaxation in borderline patients • Borderline patients respond to psychophysiological relaxation interventions.