Neurovisceral phenotypes in the expression of psychiatric symptoms.

Jessica A. Eccles,Christopher J. Mathias,Andrew P. Owens,Satoshi Umeda,Hugo D. Critchley

doi:10.3389/fnins.2015.00004

Abstract

This review explores the proposal that vulnerability to psychological symptoms, particularly anxiety, originates in constitutional differences in the control of bodily state, exemplified by a set of conditions that include Joint Hypermobility, Postural Tachycardia Syndrome and Vasovagal Syncope. Research is revealing how brain-body mechanisms underlie individual differences in psychophysiological reactivity that can be important for predicting, stratifying and treating individuals with anxiety disorders and related conditions. One common constitutional difference is Joint Hypermobility, in which there is an increased range of joint movement as a result of a variant of collagen. Joint hypermobility is over-represented in people with anxiety, mood and neurodevelopmental disorders. It is also linked to stress-sensitive medical conditions such as irritable bowel syndrome, chronic fatigue syndrome and fibromyalgia. Structural differences in “emotional” brain regions are reported in hypermobile individuals, and many people with joint hypermobility manifest autonomic abnormalities, typically Postural Tachycardia Syndrome. Enhanced heart rate reactivity during postural change and as recently recognized factors causing vasodilatation (as noted post-prandially, post-exertion and with heat) is characteristic of Postural Tachycardia Syndrome, and there is a phenomenological overlap with anxiety disorders, which may be partially accounted for by exaggerated neural reactivity within ventromedial prefrontal cortex. People who experience Vasovagal Syncope, a heritable tendency to fainting induced by emotional challenges (and needle/blood phobia), are also more vulnerable to anxiety disorders. Neuroimaging implicates brainstem differences in vulnerability to faints, yet the structural integrity of the caudate nucleus appears important for the control of fainting frequency in relation to parasympathetic tone and anxiety. Together there is clinical and neuroanatomical evidence to show that common constitutional differences affecting autonomic responsivity are linked to psychiatric symptoms, notably anxiety.

Highlights

Influential theories argue that bodily states of arousal are a key component to emotions, and are the basis to emotional feeling states
These findings endorse the proposal that Postural Tachycardia Syndrome patients are constitutionally vulnerable to anxiety symptoms through abnormalities in central mechanisms controlling autonomic reactions
Postural Tachycardia Syndrome patients showed generalized stimulus-evoked cardiovascular responses and did not show the distinct differences across emotion categories that was observed in controls and reported in previous studies (Ekman et al, 1983; Critchley, 2005)

Summary

INTRODUCTION

Influential theories argue that bodily states of arousal are a key component to emotions, and are the basis to emotional feeling states. The mechanisms underlying these brain-body interactions can be defined by combining brain imaging with detailed physiological monitoring of psychiatric and neurological patients and healthy controls. JOINT HYPERMOBILITY Clinical picture Joint hypermobility affects up to 20% of the general population (Mulvey et al, 2013) yet is often poorly recognized (Grahame, 2008) It is characterized by a variation in the type and distribution pattern of collagen. Criteria Major 1 and Minor 1 are mutually exclusive as are Major 2 and Minor 2

Conclusions

Findings

CONCLUSIONS