Impact of Overall and Specific Dimensions of Schizotypy on Theory of Mind.

Abstract

Background: Impairments in theory of mind (ToM) are highly prevalent among individuals with schizophrenia, resulting in substantial functional deficits. However, research on impairments in individuals with schizotypy has yielded inconsistent findings, with some studies finding ToM deficits in overall schizotypy, other studies finding ToM deficits in only specific schizotypy dimensions, and yet other studies finding no ToM deficits at all. One potential key factor that may account for this discrepancy is the use of schizotypy measures that do not adequately measure specific schizotypy dimensions. Additional limitations are employment of ToM measures that rely heavily on explicit cultural knowledge, verbal/reading comprehension, and/or other cognitive abilities.

Method: To address these discrepant findings, we used the Schizotypal Personality Questionnaire-Brief Revised (Updated; SPQ-BRU) and the Multidimensional Schizotypy Scale (MSS) to tap overall schizotypy and specific schizotypy dimensions. To measure ToM, we used the Frith-Happé animations (FHA) and Strange Stories Film Task (SSFT). We examined the hypothesized negative relationship between schizotypy and ToM in a sample of 233 nonclinical individuals.

Results: Regression analysis indicated no significant relationship between overall schizotypy and ToM on both the FHA (b = 0.01, t(196) = -0.75, p = 0.46) and SSFT (b = -0.20, t(195) = -1.69, p = 0.09). However, it did find that the negative schizotypy dimension was associated with poorer ToM performance on both the FHA (b = -0.11, t(194) = -2.7, p = 0.008) and SSFT (b = -0.12, t(193) = -3.22, p = 0.001). Also, exploratory analyses employing an extreme-group design approach indicated high schizotypy and high negative schizotypy groups displayed weaker ToM performance within all specific schizotypy dimensions.

Conclusion: These results indicate that ToM impairments are present in schizotypy, especially within the negative schizotypy dimension. The results suggest important methodological implication for studying ToM in schizotypy and conceptualizing the latent structure of schizotypy.