Effects of transcutaneous cervical vagus nerve stimulation on autonomic function in posttraumatic stress disorder and opioid use disorder.

The vagus nerve has branches that extend to the brain and a number of peripheral organs. Vagus nerve stimulation (VNS) affects autonomic function through enhancement of parasympathetic activity and suppression of sympathetic activity. Because of these effects VNS has a number of potential therapeutic applications. This review focuses on the effects of transcutaneous cervical VNS (tcVNS) on autonomic function in two stress-related psychiatric disorders that are characterized by increased sympathetic function, posttraumatic stress disorder (PTSD) and opioid use disorder (OUD). We have studied the effects of tcVNS on physiology in patients with PTSD and OUD with brain imaging, blood biomarkers, and wearable sensing devices. These studies demonstrated that tcVNS has effects on autonomic tone, cardiovascular function, inflammatory responses, and central brain areas involved in the modulation of emotion, that are favorable in terms of promoting recovery for patients with PTSD and OUD, in particular through effects that mitigate autonomic system dysregulation that underlies the symptomatology of these disorders. The effects of tcVNS on autonomic function and other stress-related circuits and systems show promise for development of interventions for these stress-related disorders that are related to the underlying neurobiology.