Our facial expressions give the most effective social and emotional hints of non-verbal information. Some studies show that schizophrenic patients have an impaired skill of recognizing facial expressions. Various meta-analyses of functional magnetic resonance imaging and EEG studies consistently demonstrate that schizophrenic patients have impairments in processing facial expressions.
Of the event-related potentials (ERP) that appeared during the recognition of emotions by schizophrenic and healthy male patients (when they saw frightened, happy and sad faces) in a current study conducted in 2020, the N170 and P3a responses were analyzed. N170 can be used to assess facial recognition. N170 is believed to be reflecting the early phase of facial processing. On the other hand, the P3a wave, which occurs as a response to new stimuli, reflects spontaneous and involuntary attention.
In the study, the subjects were shown the pictures of neutral faces, sad faces, happy faces and frightened faces as emotional stimuli. The subjects were asked to click the mouse button when they could see the pictures of neutral faces (targets). At this point, it was possible to analyze at which stages the patients were capable of recognizing the facial expressions or when they responded or did not respond to stimuli.
Schizophrenic patients were found to have shown bilaterally-significant smaller N170 amplitudes to neutral faces, compared to the healthy subjects. It was found that emotion (frightened, happy and sad faces) had no significant fundamental effect on the N170 in neither group. The schizophrenia group had a significantly smaller P3a amplitude as a response to the frightened and happy faces, compared to the control group. However, no significant difference could be found between the groups regarding the responses given to sad faces. It is estimated that the low P3a amplitude given to the frightened and happy faces in schizophrenic patients could be associated with the emotional recognition deficiencies of the patients.
In brief, this study set forth that the schizophrenic patients had significant reductions of P3a in the frightened and happy faces and that there were no group-based significant differences in the responses given to the sad faces by ERP during emotional recognition.
Consequently, the failure of processing of some facial expressions in schizophrenic patients can be a factor that constitutes major problems in interpersonal interactions. This case could be the underlying reason of certain impairments in the social skills of schizophrenic patients.
Onitsuka, T., Spencer, K. M., Nakamura, I., Hirano, Y., Hirano, S., McCarley, R. W., … Niznikiewicz, M. A. (2020). Altered P3a Modulations to Emotional Faces in Male Patients With Chronic Schizophrenia. Clinical EEG and Neuroscience.