Ultra-brief pulse ECT in bipolar and unipolar depressive disorder: differences in speed of response

Objectives:  There is little evidence for differences in response and speed of response to electroconvulsive therapy (ECT) between patients with bipolar and patients with unipolar depressive disorder. In the only prospective study to date, Daly et al. (Bipolar Disord 2001; 3: 95–104) found patients with bipolar depression to show more rapid clinical improvement and require fewer treatments than unipolar patients. In this study, response and speed of response of patients with unipolar and bipolar depression treated with ultra-brief pulse ECT were compared.
Methods:  All patients (n = 64) participated in a randomized trial comparing ultra-brief pulse bifrontal ECT at 1.5 times seizure threshold and unilateral ECT at 6 times seizure threshold. Thirteen patients (20.3%) had DSM-IV-defined bipolar depression. The Hamilton Rating Scale for Depression and Clinical Global Impression scale were administered at baseline and repeated weekly during and after the course of treatment by a blinded rater. At the same time point, the Beck Depression Inventory and the Patient Global Impression scale were administered. Speed of response was analyzed using survival analyses.
Results:  Patients with bipolar and unipolar depression did not differ in rates of response or remission following the ECT course, nor in response to unilateral or bifrontal ECT. Patients with bipolar depression, however, showed a more rapid response than patients with unipolar depression.
Conclusions:  Patients with bipolar depression tend to show more rapid clinical improvement with ECT than patients with unipolar depression.