Theory of mind impairments in individuals at ultra-high risk for psychosis

Abstract

Objectives To determine deficits in theory of mind in individuals at ultra-high risk for psychosis (UHR), and to explore the relations between theory of mind and symptom severity. Methods 27 ultra-high-risk patients in clinics of the Peking University Sixth Hospital and 25 normal controls in community were enrolled from April 1st, 2014 to March 30th, 2015. The Structured Interview for Prodromal Syndromes (SIPS), Positive and Negative Syndrome Scale (PANSS) were used to evaluate all of the individuals in both groups. Theory of mind was assessed with the false belief task, the hinting task, the reading the mind in the eyes test (eye task) and the faux pas task. Chi square test, t test and non parametric test were used to compare all of the theory of mind tasks between the two groups. Pearson correlation and Spearman correlation were used to analyze the correlations between theory of mind and psychopathology in the UHR. Results The total scores of SIPS and PANSS in the UHR group were 27.2±10.5 and 48.6±9.1. The performance of faux pas task (0.80(0.60,0.88) vs. 0.90(0.85,0.92), Z=-3.64, P<0.01 ) , hinting task (18(17,19) vs. 19(19,20), Z=-3.02, P<0.01) and eye task (22.7±3.3 vs. 23.8±3.4, F=4.40, P<0.05) in UHR remained significantly poorer as compared with the control group when controlled for IQ. Effect sizes were 1.16, 0.79 and 0.33 respectively. The two groups were compared at the false belief task. In the UHR group, there were still statistically correlations between two negative symptoms and the hinting task after correction, which were the item of avolition (r=-0.63, P<0.01) and item of reduced ideational richness (r=-0.52, P< 0.01). Conclusion There are possible deficits in higher order theory of mind in UHR, and the negative correlation might exist between higher order theory of mind and negative symptoms. Key words: Schizophrenia; Theory of mind; Ultra-high risk