Clinical symptomatology and theory of mind in schizophrenia: Which relationship?

Abstract

Introduction

Theory of mind (ToM) has repeatedly been shown to be compromised in many patients with schizophrenia (SCZ). It now seems to be quite well-established that patients with profound negative or disorganized symptoms perform poorly on ToM tasks. By contrast, findings in patients with predominant positive symptoms are much more ambiguous.

Objectives

To investigate the relationship between ToM deficits and different symptoms dimensions in SCZ.

Methods

Fifty-eight outpatients with stable SCZ completed the intention-inferencing task (IIT), in which the ability to infer a character's intentions from 28 short comic strip stories is assessed. Symptomatology evaluation comprised the Positive and Negative Syndrome Scale (PANSS), the Calgary Depression Scale for Schizophrenia (CDSS) and the Clinical Global Impressions Scale Improvement and severity (CGI).

Results

The number of correct answers in the IIT negatively correlated with both the positive (P = 0.015) and negative (P < 0.0001) scales of the PANSS. ToM deficits were correlated with the conceptual disorganization, hallucinations and the suspiciousness/persecution items.

The patients who had more false answers in the IIT also had significantly higher scores at the positive (P = 0.005), negative (P < 0.0001) and general (P < 0.0001) scales of the PANSS. Worse IIT performance correlated with a higher severity index in the CGI. No correlations were found between IIT scores and CDSS scores.

Conclusions

Our results confirm the relationship between ToM deficits and negative symtomps and suggest that ToM may also be correlated to specific positive symptoms.

Disclosure of interest

The authors have not supplied their declaration of competing interest.