Neurophysiological Responses and Behavioural Intentions to Schizophrenia-Associated Communication Abnormalities
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Background: Little is known about how abnormal communication from someone with schizophrenia is perceived by those interacting with the individual. The N400 event-related potential (ERP) is an index of how difficult it is to process incongruent words and is sensitive to context about the identity of the speaker. Knowledge of an individual’s diagnosis provides such context, and responses to a diagnosis have typically been examined from a stigma framework. Purpose: The current study aimed to examine the effect of context regarding the speaker, on the N400 ERP in the listener in response to speech that contained schizophrenia-associated communication abnormalities, and the relationship between the N400 and stigma. Methods: 73 first year undergraduate students listened to segments of conversation between two people while continuous EEG was recorded. Participants were told that the responder in the conversation was either a university student, had a stroke, had schizophrenia (and had recovered), or had schizophrenia (and symptoms were emphasized). The last word of the response in the conversation was varied to be a typical ending, a word approximation, or a neologism. Results: A significant N400 was observed over centro-parietal electrode sites in response to word approximations and neologisms when participants were told that the responder was a university student, but not in the other conditions. The amplitude of the N400 was significantly greater in response to neologisms than in response to word approximations. Participants also rated that they would be more likely to continue speaking to someone using typical words, than word approximations, and in both cases, more like than someone using neologisms. There was no significant relationship between the amplitude of the N400 and any of the stigma measures. Discussion: Telling participants either about the functional symptoms of schizophrenia, the diagnosis, or both resulted in a significantly reduced N400. This suggests a processing bias in which knowledge of either the symptoms or diagnosis of schizophrenia reduces the difficulty of integrating atypical speech. This does not appear to be a result of stigmatizing attitudes per se, but may be the result of an expectancy for someone with schizophrenia to communicate in abnormal ways.