The nature of emotional abnormalities in schizophrenia: Evidence from patients and high-risk individuals

Schizophrenia is a psychiatric disorder that affects about one out of 100 people with symptoms generally emerging in early adulthood. According to the DSM-IV, schizophrenia is characterized by psychotic symptoms, such as hallucinations, delusions, bizarre behavior or speech and negative symptoms such as flattening of affect. Psychotic symptoms such as hallucination and delusions are regarded as particularly characteristic for schizophrenia, although they may also occur in other psychiatric disorders. Besides these psychotic symptoms, which are often treatable with antipsychotic medication, people with schizophrenia experience negative symptoms (social withdrawal, affective flattening, apathy, alogia) and cognitive disturbances, e.g. memory dysfunction, attention problems, and emotional dysfunction. It are mainly these latter problems that cause that the majority of people with schizophrenia are unable to built up a social network, career and romantic relationships, making it one of the most invalidating psychiatric disease. Currently, the prevalent idea is that emotion processing is generally deficient in schizophrenia. Thus, the emphasis is solely on reductions or impairments. However, some studies suggest that schizophrenia is associated with a reduced ability to perceive and express emotions, with at the same time intact or even heightened emotional experience. This disjunction between emotional processes in schizophrenia was investigated in more detail. Second, this thesis dealt with investigating the presence of emotional abnormalities in individuals high on the schizophrenia spectrum continuum. Emotional abnormalities in people at high-risk for schizophrenia are hypothesized, because emotional abnormalities appear to be a core feature of schizophrenia and would therefore be expected to be present to a certain degree in high-risk individuals. Finally, we investigated the influence of social-emotional aspects on other cognitive functions, such as decision-making, in patients with schizophrenia and individuals at high-risk for schizophrenia. The most important findings are that emotional abnormalities appear to be central to schizophrenia and are also present in individuals with a liability for schizophrenia-like traits or an increased genetic risk. This suggests that emotional abnormalities can be regarded as a vulnerability marker for schizophrenia. However, these emotional abnormalities do not reflect an overall reduction in all aspect of emotion processing, i.e. perception, expression, experience and psychophysiology. Instead, schizophrenia patients and individuals at high risk report normal or higher levels of emotional experience, whereas the expression of emotions appears deficient. With respect to the perception of emotion, results depend on the type of processing that occurs, i.e. automatic, incidental processing or controlled, elaborative processing of affective information. These findings suggest a disjunction between deficits in elaborative processing of emotions on the one hand, and normal or increased emotional reactivity on the other hand. Moreover, deficits in the perception and expression of emotions appear to be consistently related to negative symptoms, such as blunted affect and social emotional withdrawal. In addition, positive symptoms might be related to an increased subjective emotional arousal. The finding of a particular pattern of emotional abnormalities in patients with schizophrenia and individuals at high risk for schizophrenia could give clues about the underlying brain pathology and ultimately the development of treatment strategies that selectively target those brain systems.