Many studies have found that patients with schizophrenia find it more difficult to recognise facial emotions. This makes it harder to work out other people's feelings leading to problems with social interactions and a declining sense of social worth. In healthy people the basic emotions - happiness, sadness, fear, anger, disgust and surprise - tend to be perceived in a categorised way with sharp, clear-cut boundaries between them. Recent research, using sophisticated animation techniques, has shown that in schizophrenia patients the categories are less sharp with more uncertain boundaries leading to more potential for misinterpretation. A French study which compared 26 patients with schizophrenia to 26 healthy controls found that people with schizophrenia had less distinct perceptual boundaries between different emotions which in turn led to confusion between emotions and the potential for reading people's emotions in a radically wrong way. The researchers suggested that these impairments in emotional perception could lead to false perceptions of others' emotions and the development or maintenance of delusional ideas.
Vernet, Mathilde, Baudouin, Jean-Yves and Franck, Nicolas - Facial emotion space in schizophrenia Cognitive Neuropsychiatry 2008, 13(1), 59-73