Deficient Emotional Intelligence and Dysfunctional Early Emotional Prosody Processing Varying with the Severity of Auditory Hallucinations in Schizophrenics

Background Most individuals with schizophrenia (SPs) experience auditory hallucinations (AH) of a negative or threat-related nature; however, the impact of AH on the early perceptual processing of emotions at the auditory cortex remains relatively unknown. In this paper, we employed an implicit emotional task to investigate the effects of AH on the early central processing of emotional prosody (within 100 milliseconds after stimulus onset) in SPs. We hypothesized that abnormalities in the emotional responses of SPs may vary with the severity of AH and may also be associated with impaired social cognition. Methods and findings A total of 63 SPs with AH of various severities and 21 age-matched control participants (CP) were recruited for this study. We assessed clinical symptoms and emotional intelligence (EI) as an index of social cognition. Auditory responses, including M50 and M100 components, to neutral and emotional prosody (happy, sad, angry, and fearful) were recorded using magneto encephalography. We then compared the groups in terms of the emotion-specific responseindex scores (normalized by the response to neutral sound) followed by correlation analysis with EI performance. Our results revealed that SPs have a delayed M50 response to the sad prosody; compared to CPs. SPs with ongoing AH invoked faster M50 responses to the angry prosody, compared to SPs without AH. In cases of persistent AH, we found that SPs with worse EI performance exhibited faster M50 responses to negative-laden prosody. Conclusion This study revealed that AH influence early emotional responses at the low level of auditory processing. Dysfunction in the processing of less emotionally salient stimuli (sadness) may be a trait-feature of schizophrenia. Nevertheless, a predilection toward negative emotions with high arousal in persistent AH may act as a state-feature incurring the impairment of social cognition. These findings provide insight into the neural mechanisms underlying distinct phenotypes of SPs (with or without AH).