Social cognition in schizophrenia

Schizophrenia is a chronic psychiatric disorder, incorporating a wide range of symptoms that may occur at certain stages of the disease. The core symptoms can largely be divided into positive symptoms, e.g. hallucinations and delusions, and negative symptoms, e.g. apathia and emotional flattening. Schizophrenia is also known to be associated with social cognitive impairments. In particular, emotion recognition, i.e., the ability to infer emotional information from facial expressions, and theory of mind (ToM), i.e., the ability to infer the intentions and beliefs of other individuals, appear to be for schizophrenia important domains of social cognition, because they are valid predictors of social functioning of the patients. This thesis describes five studies on social cognition in schizophrenia. First, in a family study including schizophrenia patients and their siblings, we show that social cognitive impairments are related to schizophrenia symptoms. Suggestive of a common familial basis, social cognitive functioning clusters between siblings. Second, in a longitudinal study investigating emotion recognition in schizophrenia patients, we show that emotion recognition impairments are present in non-acute stages of the illness. However, the study also shows further deterioration of emotion recognition deficits during acute phases of the disorder. Third, in a study investigating brain structures using Magnetic Resonance Imaging techniques, we show that reduced prefrontal cortex, but not amygdala gray matter volume is associated with social cognitive deficits in schizophrenia. Fourth, in an epidemiological study investigating Quality of Life (QOL) of patients, we show that ToM rather than emotion recognition is associated with QOL, and this association is moderated by schizophrenia symptoms. In particular, patients with relatively unimpaired ToM and more severe schizophrenia symptoms have poor QOL. Insight could be a possible explanation for the findings, i.e., more severely ill patients with relatively unimpaired ToM may be more aware of the effects of their illness on their social environment. In the final study of this thesis, we investigate the effects of two anti-psychotic medications, i.e., aripiprazole versus risperidone, on social cognition in schizophrenia. In an eight week open-label trial we show that aripiprazole and risperidone have similar impact on social cognitive performance. However, aripiprazole treatment has a greater effect on patients’ processing speed compared to treatment with risperidone. Taken together, this thesis contributes to the knowledge on social cognition and its structural brain correlates in schizophrenia and elucidates associations between social cognitive performance and both QOL and anti-psychotic drug therapy. The current findings show that social cognition in schizophrenia is a relevant construct for basic science as well as clinical practice and, therefore, deserves attention of future research.