The relation of schizotypy and cognition with theory of mind in first-degree relatives of patients with diagnosis of schizophrenia

Objective: Many of studies have reported that patients with schizophrenia have Theory of Mind (ToM) deficits. Also, investigations in first degree relatives of schizophrenia patients have reported that ToM deficits may be a candidate of endophenotype for schizophrenia. The aim of this study was to asses the ToM abilities and its relations with neurocognition and schizotypal traits in patients with schizophrenia and their first degree relatives. Method: 25 patients with schizophrenia, their unaffected 25 first degree relatives and 30 healthy controls included. To asses ToM, we have used Dokuz Eylül Theory of Mind Index (DEToMI) and to asses neurocognition, we have used Neuropsychological Test Batery for all participants. Patients were assesed with Positive and Negative Syndrome Scale ( PANSS) to measure clinical situation. First degree relatives and controls were assesed with Structured Interview for Schizotypy-Revised (SIS-R) to evaluate schizotypal traits. All participants were assesed with Hamilton Depression Rating Scales to measure depressive symptoms. Results: In first-degree relatives, "faux pas" task scores were found lower than controls and neurocognitive functions were found worser than controls but not in all neurocognitive tests. In relatives, we have found only one strong correlation about ToM task and neurocognitive tests relations. Schizoytpal traits were higher than controls for some subscales. "Faux pas" and "suspiciousness" were correlated with middle power in relatives. In patients, all ToM task scores were lower than controls and many of neurocognitive tests scores were found lower than controls. Weak and middle correlations were found between ToM and neurocognitive measures. Conclusion: In our study, we have found ToM deficits in patient with schizophrenia and their first degree relatives. But, ToM deficists grade of relatives were among the patients and controls. We found similar results for neurocognitive functions. There are relations between ToM and neurocognitive functions but we have found that degree of relations were substantially weak and middle. Also, in relatives, schizotypal traits were higher and one subscale of Tom and SIS-R were correlated with a middle power. Our results means, ToM has relations with neurocognitive function and schizotypal traits but the grade of this relations are little-middle. This study suggests that ToM may be a candidate of endophenotype for schizophrenia. Keywords: Theory of Mind, Neurocognitive Functions, Schizotypal Traits, Endophenotype