Heart Rate Variability, Autonomic Reactivity, and Emotion Regulation during Sadness Induction in Somatic Symptom Disorder.

Background: Preliminary evidence suggests altered heart rate variability (HRV) and impaired emotion regulation (ER) in somatic symptom disorder (SSD). Moreover, HRV can be considered an index of ER. Yet, to date, research on HRV and emotional reactivity in SSD is scarce and findings are inconsistent. Thus, this study aimed to examine ER differences, HRV at rest, and in response to emotion induction in persons with SSD compared to controls.

Methods: The sample comprised 44 persons with SSD (DSM-5; 79.5% female, M_age = 45.7, SD = 14.7) and 41 persons without SSD (non-SSD; 78% female, M_age = 44.2, SD = 14.7). We assessed the participants' somatic symptom severity, ER, and control variables (e.g., depressive symptoms). Frequency and time domain HRV by ECG and subjective emotional states were measured at rest, under sadness induction, and during recovery periods. We evaluated baseline between-group differences with t-tests, and HRV and emotional reactivity and recovery with repeated measures ANOVAs.

Results: We found no significant differences in resting state HRV between persons with and without SSD. Regarding reactivity and recovery, SSD group showed lower reactivity in SDNN (standard deviation of NN interval) than non-SSD group. Moreover, SSD group reported more maladaptive ER techniques (e.g. rumination) and a higher effort to regulate their emotions during the experiment than non-SSD group.

Conclusions: The study indicated impaired ER in persons with SSD. This finding showed more clearly in self-report than in HRV. Further research on HRV reactivity including tasks evoking other negative emotions in persons with SSD is required.