Behavioral evidence of blunted and inappropriate affective responses in schizophrenia: Lack of a 'negativity bias'

There have been debates about the nature of impairment in the processing of emotional information in schizophrenia. Meanwhile, there is a generally accepted principle referred to as a 'negativity bias', which means a general tendency to process negative emotional information with priority to positive emotional information. To investigate the impairment in emotional processing and the existence of a 'negativity bias' in schizophrenia, we developed an experimental task. In this task, the response characteristics in four emotional conditions (positive, negative, combined and neutral) were compared between the patient and control groups. Twenty-five patients with schizophrenia and the same number of controls performed the emotional response task, in which the subjects were required to respond according to their subjective feelings as quickly and correctly as possible after observing the stimuli. In the positive emotional condition, the positive responses were significantly reduced in the patient group compared with the control group. In particular, the patient group showed the poorest performance in the negative emotional condition. In the combined emotional condition, where positive and negative emotional stimuli were simultaneously presented to the subjects, the control group tended to choose 'negative' responses most frequently, whereas the patient group chose positive and negative responses at similar rates. These results indicate that the patients with schizophrenia show restricted and inappropriate responses to emotional stimuli and have a differential deficit in the immediate and hierarchical processing of negative emotional information.