Psychiatry Research EG

Introduction Recent studies on bipolar disorder (BD) have reported a deficit in social recognition and emotional deficit even in the remission period of the disorder. Given that impaired social cognition in patients with serious mental illness impacts on increased symptom severity, prolonged course of illness, higher rates of relapse, and daily functioning, characterization of the extent of these deficits is important. Aim of the study The aim of this study was to examine differences in social cognition insamples of euthymic patients with first-episode BD type I, their unaffected biological full siblings, and healthy participants, as well as to determine whether the between-group differences reported above were mediated by clinical characteristics in euthymic patients. Patients and methods The study included 90 participants: 30 euthymic male patients with first-episode BD type I diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, 4th ed.; 30 unaffected full siblings of the euthymic patients; and 30 healthy controls. The three groups were matched as regards age, sex, education, marital status, and employment. All participants were subjected to social cognitive assessment using the reading the mind in the eyes (_eyes task_), to assess the emotional aspects of theory of mind (ToM), and the ToM’s pictorial story tasks. Results The patients and their unaffected biological full siblings were significantly impaired in social cognition relative to controls assessed using the eye task and the pictorial story task (Po0.001 and <0.0001, respectively). Compared with unaffected siblings, patients with BD performed poorly on the emotional and cognitive tasks. Conclusion Our study suggests that euthymic patients with BD type I have deficits in cognitive and emotional ToM. In fact, it can be concluded that the deficits in social cognition may be endophenotypic markers of genetic vulnerability to BD type I. Keywords: biological siblings, euthymic bipolar disorder, social cognition