The relationship between ECT responsiveness and subtypes of tardive dyskinesia in bipolar patients.

Despite intensive research, the mechanisms of action of electroconvulsive therapy (ECT) remain elusive. In addition, there are no known biological factors predicting ECT responsiveness in bipolar patients. A study was conducted to investigate the relationship between ECT responsiveness and tardive dyskinesia (TD), a common side effect of neuroleptic therapy, and its subtypes (i.e., orofacial and limb-axial dyskinesias) in a group of 18 bipolar patients. There was a significant difference in orofacial dyskinesia scores between ECT responders and non-responders (p less than 0.005), while there was no significant association in scores of limb-axial dyskinesia between ECT responders and non-responders. These findings suggest an association between ECT responsiveness and the presence of orofacial dyskinesias in bipolar patients with TD and add further support to the notion that TD is a heterogeneous disorder comprising at least two subtypes with distinct underlying pathophysiological mechanisms.