Characterization of the facial expression of emotions in schizophrenia patients: preliminary findings with a new electromyography method.

OBJECTIVE We investigated facial expression of emotions (FEE) in schizophrenia patients, using an improved and highly selective facial electromyography (EMG) method, and we examined the correlation between FEE and psychopathology. METHOD We compared unmedicated patients with schizophrenia (n = 32) with healthy subjects (n = 21) with regard to the activity of 3 joy-relevant facial muscles (the M.zygomaticus, the M. orbicularis oculi, and the M.levator labii). Emotions were induced by pictures from the International Affective Picture System. We measured previsible muscle activity with a new, highly selective facial EMG. We used the Positive and Negative Syndrome Scale to evaluate psychopathology. RESULTS Patients with schizophrenia showed fewer joy or smile reactions than did control subjects and displayed decreased activity of the M.orbicularis oculi and M.zygomaticus under presentation of positive pictures. Reduced activity of these muscles can be caused by depression. Increased activity of the M. levator labii correlates with positive symptoms. CONCLUSIONS Our findings indicate that psychopathological syndromes correlate with schizophrenic mimic disturbances. These results can be used to compare various antipsychotics with regard to their influence on mimic disturbances.