Neural mechanisms underlying theory of mind application deficits in bipolar mania: an event-related potential study

Theory of Mind (ToM) impairment is observed in bipolar disorder (BD) across mood states and may be more pronounced during manic episodes. However, the neurophysiological basis of ToM application—particularly the temporal relationship between posterior perspective-related processing and later frontal processing during perspective selection and conflict management—remains poorly understood. Nineteen patients who met ICD-10 criteria for a bipolar manic episode and twenty-four healthy controls completed a rapid ToM judgment task while electroencephalography (EEG) was recorded. Manic symptoms in the patient group were subthreshold according to established YMRS cutoffs at the time of assessment. Behavioral performance and event-related potentials (ERPs) were analyzed. The TP450 component (325–525 ms), associated with posterior perspective-related processing, and the Late Frontal Slow Wave (LFSW; 600–800 ms), treated as a marker of later frontal processing during perspective selection and conflict management, were examined. Compared with healthy controls, patients with BD showed reduced accuracy and prolonged reaction times across all conditions. ERP analyses revealed significantly attenuated TP450 amplitudes at right parietal sites (P4) in the BD group, consistent with altered posterior perspective-related processing. Patients also exhibited reduced LFSW amplitudes at left frontal sites (F3), consistent with altered recruitment of later frontal processes during the task. In this small clinical sample, the findings provide preliminary evidence for differences in posterior perspective-related processing and subsequent frontal processing during ToM application. The results require replication in larger, independent samples before they can be generalized to the broader population of patients with bipolar disorder. Not applicable.