Editorial: Dysregulation of Autonomic Cardiac Control by Traumatic Stress and Anxiety

“Disorders of arousal” were defined in the past in terms of brain-based hypersensitivity to environmental stimulation (Gellhorn, 1968). Normally balanced sympathetic and parasympathetic branches of the autonomic nervous system (ANS) was historically described as “autonomic tuning,” in contrast to the disorders of arousal which are characterized by ANS dysfunction, affective lability, anxiety, stress, and emotional disorder (Gellhorn and Loofburrow, 1963; Everly and Lating, 2012). Recent studies of the relevance of the ANS to stress and mental disorders are becoming increasing in number1 (Agorastos et al., 2015). ANS dysregulation impacts on both physical (increasing cardiovascular risk) and mental (compromising psychological well-being) health at multiple levels. Loss of regulation of normal autonomic control of cardiac adjustment to environmental stressors thus leads to negative impacts on physiological function affecting arterial blood pressure, heart rate and rhythm, and vagal afference. Allostatic load is a term that has been used for decades to describe “the wear and tear on the body” which grows over time when the individual is exposed to repeated or chronic stress (McEwen and Stellar, 1993). Allostatic load is the physiological consequence of chronic exposure to fluctuating or heightened neural or neuroendocrine response that results from repeated or chronic stress. Thus it is, chronic autonomic imbalance finally leads to allostasis of affective, cognitive, and behavioral level of function. While the older “Disorders of Arousal” model continues to be prevalent in the scientific and clinical literature on stress-related pathogenesis, the field of stress disorders has taken great strides forward in terms of the NIMH-supported Research Domain Criteria (RDoC) initiative2. RDoC has successfully redefined “mental disorders” as “brain circuit disorders” using a matrix to organize increasing units of levels of analysis (genes through self-report and paradigms) for studying precisely defined domain constructs describing behavior. Most importantly, is that application of the RDoC approach brings into focus new therapeutics and new targets of therapeutics for brain disorders (Insel and Cuthbert, 2015). This is exactly where the articles that comprise the Frontiers Research Topic: “Dysregulation of autonomic cardiac control by traumatic stress and anxiety” fit into clinical practice and research. Research data over the past two decades are showing that heart rate variability (HRV) is diminished in anxiety and stress-related disorders including PTSD, and lower HRV signals a disturbance