Theory of Mind as an endophenotype for schizophrenia spectrum disorder: Study in first episode of psychosis patients and first-degree relatives

Georgelina Abreu-Fernández; Nancy Murillo-García; Víctor Ortiz-García de la Foz; Rebeca Magdaleno Herrero; Ángel Yorca-Ruiz; Rosa Ayesa-Arriola

doi:10.1016/j.sjpmh.2023.09.004

Theory of Mind as an endophenotype for schizophrenia spectrum disorder: Study in first episode of psychosis patients and first-degree relatives

Span J Psychiatry Ment Health. 2023 Oct 12:S2950-2853(23)00039-X. doi: 10.1016/j.sjpmh.2023.09.004. Online ahead of print.

Authors

Georgelina Abreu-Fernández¹, Nancy Murillo-García¹, Víctor Ortiz-García de la Foz², Rebeca Magdaleno Herrero¹, Ángel Yorca-Ruiz¹, Rosa Ayesa-Arriola³

Affiliations

¹ Research Group on Mental Illnessess, Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain; Doctoral School University of Cantabria (EDUC), Santander, Spain.
² Research Group on Mental Illnessess, Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain; Centro Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain.
³ Research Group on Mental Illnessess, Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain; Centro Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain; Department of Psychiatry, University Hospital Marqués de Valdecilla, Santander, Spain. Electronic address: rayesa@humv.es.

PMID: 38591834
DOI: 10.1016/j.sjpmh.2023.09.004

Abstract

Background: Deficits in Theory of Mind (ToM) had been suggested as a possible endophenotype for unaffected relatives of first episode of psychosis (FEP) patients. There are a limited number of studies which have evaluated ToM deficits among the siblings and parents of FEP patients.

Aim: This study aimed to explore ToM deficits and its correlates among FEP patients, their siblings, parents, and controls.

Methodology: FEP patients (N=102), their parents (N=135), siblings (N=97), and controls (N=167) were evaluated on ToM performance with the Reading the Mind in the Eyes Test (Eyes Test). Interview for sociodemographic variables of age, sex, years of education, and IQ estimation and neurocognitive tests were administered to all groups.

Results: FEP patients had a significantly lower performance on the Eyes Test compared to their siblings and controls. However, no significant differences were found between siblings and parents or siblings and controls.

Conclusion: Attending our results, we found no evidence for ToM deficits as an endophenotype of SSDs. Furthermore, ToM accuracy may be mediated by interaction with other cognitive domains and play a protective role against psychosis in unaffected siblings.

Keywords: First degree relatives; First episode of psychosis; Relatives; Schizophrenia; Theory of Mind.