Investigation of social cognitive functions in familial risk group for psychosis

OBJECTIVE: Social cognitive functions are important for social functioning and healthy social interactions. Social cognitive dysfunctions have been reported in the acute phase of psychosis as well as in remission. They are even present in the prodromal phase and also in individuals with familial risk for psychosis. These findings suggest that social cognitive dysfunction may be a trait-marker for schizophrenia . The aim of our study is to analyze social cognitive dysfunctions in individuals with familial risk for psychosis and to evaluate their association with schizotypal features, neurocognitive functions and childhood traumas. METHOD: 34 healthy siblings of schizophrenic patients and 34 healthy volunteers matched for age, gender and years of education were included in the study. All participant were assessed with, SCID-I / CV, Dokuz Eylül Theory of Mind Index (DEToMI), Reading the Mind in the Eyes Test (RMET), Structured Interview for Schizotypy-Revised (SIS-R), Childhood Trauma Questionnaire (CTQ), Stroop Test, Verbal Fluency Test, Personal and Social Performance Scale (PSP), Toronto Alexithymia Scale (TAS), Difficulty in Abstract Thinking item of Positive and Negative Syndrome Scale (PANSS), Beck Depression Inventory (BDI). RESULTS: Familial risk group and healthy control group were matched in terms of age, gender and year of education. In the familial risk group theory of mind impairment was observed. The familial risk group performed worse in all DEToMI subscales except the second order false belief test subscale. The ability to recognize the mental representations underlying negative emotions assessed by the reading the mind in the eyes test subscale was more impaired in the familial risk group than in the healthy control group. The schizotypal trait total score and positive and negative-disorganized subscale scores in familial risk group were significantly higher than healthy controls. Executive functions such as focused attention, sustained attention, response inhibition and resistance to distractors interference, as assessed by the Stroop test and verbal fluency test, were found to be more impaired in the familial risk group. Also, verbal fluency and theory of mind test scores were correlated in the same group. Positive schizotypal features were associated with the theory of mind in the familial risk group. Childhood Trauma Questionnaire scores were correlated with DEToMI total score and positive emotions subscale of RMET. Logistic regression analysis showed that the DEToMI total score, which assessed the cognitive dimension of the theory of mind, predicted to be a sibling of schizophrenia very strongly. CONCLUSIONS: Individuals with familial risk for psychosis showed theory of mind impairments. These impairments are affected by schizotypal traits, neurocognitive functions and childhood trauma, however this effect appears to be partial. These results support that theory of mind may be a trait-marker and endophenotype candidate for schizophrenia.