Interoception and Positive Symptoms in Schizophrenia.

Martina Ardizzi,Livia Buratta,Claudia Mazzeschi,Simone Donnari,Francesca Ferri,Marianna Ambrosecchia,Maurizio Peciccia,Vittorio Gallese

doi:10.3389/fnhum.2016.00379

Abstract

The present study focuses on the multifaceted concept of self-disturbance in schizophrenia, adding knowledge about a not yet investigated aspect, which is the interoceptive accuracy. Starting from the assumption that interoceptive accuracy requires an intact sense of self, which otherwise was proved to be altered in schizophrenia, the aim of the present study was to explore interoceptive accuracy in a group of schizophrenia patients, compared to healthy controls. Furthermore, the possible association between interoceptive accuracy and patients’ positive and negative symptomatology was assessed. To pursue these goals, a group of 23 schizophrenia patients and a group of 23 healthy controls performed a heartbeat perception task. Patients’ symptomatology was assessed by means of the Positive and Negative Syndrome Scale (PANSS). Results demonstrated significantly lower interoceptive accuracy in schizophrenia patients compared to healthy controls. This difference was not accounted for participants’ age, BMI, anxiety levels, and heart rate. Furthermore, patients’ illness severity, attention and pharmacological treatment did not influence their interoceptive accuracy levels. Interestingly, a strong positive relation between interoceptive accuracy and positive symptoms severity, especially Grandiosity, was found. The present results demonstrate for the first time that interoceptive accuracy is altered in schizophrenia. Furthermore, they prove a specific association between interoceptive accuracy and positive symptomatology, suggesting that the symptom Grandiosity might be protective against an altered basic sense of self in patients characterized by higher sensibility to their inner bodily sensations.

Highlights

“A circle is the only geometric shape defined by its centre
Results demonstrated a significant difference between schizophrenia patients (SCZ) and healthy controls (HC) for State Anxiety Inventory (STAI-I) score (SCZ: 47.23, SE 3.19; HC: 34.04, SE 1.46; t43 = 3.814, p = 0.001) and Heart Rate (HR) (SCZ: 86.48 BPM SE 16.21; HC: 76.72 BPM, SE 3.25; t44 = 2.083, p = 0.043)
Results demonstrated the absence of any significant effect of both illness severity [illness duration: R2 = 0.166; F(1,17) = 3.188; p = 0.093; β = 0.408; number of hospital admissions: R2 = 0.044; F(1,22) = 0.977; p = 0.334; Global Assessment of Functioning Scale (GAF) score: R2 = 0.156; F(1,22) = 3.877; p = 0.062]; attention [R2 = 0.054; F(1,22) = 1.204; p = 0.285; β = 0.233], and pharmacological treatment [R2 = 0.037; F(1,15) = 0.532; p = 0.478; β = 0.191] on SCZ participants’ interoceptive accuracy

Summary

Introduction

“A circle is the only geometric shape defined by its centre. No chicken and egg about it, the centre came first, the circumference follows. A significant under-estimation of individual sense of agency appeared to be related with the prevalence of negative psychotic symptoms (Maeda et al, 2013). Another intriguing aspect of the self experience, which recently gained a lot of attention, is interoception. The strict relation between interoceptive accuracy and basic self experiences finds neuroscientific support in the fact that the most salient inner bodily feelings, contributing to a “cinemascopic representation of the entire body from within”, require the Insular cortex (Craig, 2003) the brain structure involved in interoceptive processes (Pollatos et al, 2007b; Jarrahi et al, 2015). Interoceptive accuracy appeared to be compromised in several psychiatric disorders, such as anorexia nervosa, major depression, depersonalization-derealization disorders, and anxiety disorders (Pollatos et al, 2008; Furman et al, 2013; Gaudio et al, 2014; Sedeño et al, 2014; Harshaw, 2015)

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Conclusion