Impairment of social cognition in comparative studies of patients with schizophrenia and their healthy siblings.

Social cognition impairment is a significant neurocognitive disturbance observed during clinical course of schizophrenia. Deficits in this field observed in first- degree unaffected relatives have been suggested as a potential endophenotype. The main purpose of this study was to review the range of published articles on this topic, mainly from the last decade (2010-2021). A search in the online databases PubMed, Medline and Polish Medical Library using following keywords: schizophrenia, healthy sibling, social cognition, theory of mind, facial emotion recognition. Results of the review indicate on a substantial agreement on how to classify relatives' deficits in social cognition. Most analyzed studies indicate their level of neurocognitive disturbance in between schizophrenic siblings and controls. Schizophrenic patients present both theory of mind and facial emotion recognition impairment, comparable deficits have been observed to a lesser degree in their healthy siblings. It may be supposed that people with familial risk of schizophrenia may experience similar social cognition deficits as their sick relatives. Moreover, results of majority of studies reveal correlations of social cognition disturbances with cognitive dysfunctions and subclinical psychopathology in healthy siblings. However, further research on more numerous groups is needed to draw reliable conclusions on this topic.