Respiratory Sinus Arrhythmia: A Transdiagnostic Biomarker of Emotion Dysregulation and Psychopathology

Abstract

In the past two decades, respiratory sinus arrhythmia (RSA)-an index of parasympathetic nervous system (PNS)-mediated cardiac control-has emerged as a reliable peripheral biomarker of emotion regulation (ER). Reduced RSA and excessive RSA reactivity (i.e., withdrawal) to emotional challenge are observed consistently among individuals with poor ER capabilities, including those with various forms of internalizing and externalizing psychopathology, and those with specific psychopathological syndromes, including anxiety, phobias, attention problems, autism, callousness, conduct disorder, depression, non-suicidal self-injury, panic disorder, and trait hostility. Emerging evidence suggests that low RSA and excessive RSA reactivity index poor ER because they are downstream peripheral markers of prefrontal cortex (PFC) dysfunction. Poorly modulated inhibitory efferent pathways from the medial PFC to the PNS result in reduced RSA and excessive RSA reactivity. According to this perspective, RSA is a non-invasive proxy for poor executive control over behavior, which characterizes most forms of psychopathology.

Keywords: emotion dysregulation; emotion regulation; externalizing; internalizing; parasympathetic nervous system; psychopathology.

Figure 1

Fictitious heart rate (HR) signals and associated power spectra. The top two panels represent pure high-frequency HR variability (0.25 Hz), as associated with RSA. The middle two panels represent low-frequency HR variability (0.07 Hz), which is of parasympathetic, sympathetic, diurnal, and nonneural origin. The bottom panels represent the combined signal including both high- and low-frequency components. Actual heart rate signals include spectral power at additional frequencies.