Bi-temporal electroconvulsive therapy efficacy in bipolar and unipolar depression: A retrospective comparison

Although electroconvulsive therapy (ECT) has been extensively used for depressive episodes in bipolar disorder (BDD), it has received less interest in research compared with major depressive disorder (MDD). Studies comparing the efficacy of ECT in BDD and MDD have been contradictory. This study aimed to compare the effectiveness of ECT in BDD and MDD, analyzing the influence of clinical features on outcome.

The medical charts and electronic records of 107 patients (MDDn = 75 [70.1 %], BDD n = 32 [29.9 %]) receiving bi-temporal ECT were investigated retrospectively. Features of the index episode, such as the time elapsed until ECT and the effect of diagnosis on efficacy evaluated by the Hamilton Depression Rating Scale (HAM-D), were analyzed.

The diagnostic groups were alike concerning clinical features of the index episode, such as the presence of psychotic symptoms and suicidality. Patient age and the number of previous affective episodes were significantly different between the groups. The time elapsed until ECT in the examined episode was significantly longer in the MDD group. Compared with the MDD group, the BDD group had a significantly higher remission rate with ECT. Regression analysis revealed that BDD diagnosis, older age, and shorter time until ECT were significantly associated with remission.

The significant relationship observed between greater time elapsed until ECT and worse outcome is noteworthy in terms of clinical practice. This finding further challenges the widely accepted place of ECT as the "last resort" for the treatment of depression in bipolar and unipolar affective disorders.