Response to Kotzalidis et al.

To the editor: We appreciate the comments from Kotzalidis et al. regarding our recent article. In our study, linear mixed-effects modeling analysis revealed that ECT was significantly more effective than algorithm-based pharmacological treatment, and the response rate was significantly higher in the ECT group. Furthermore, shorter times to response and remission in the ECT group of better effect on remission rate was a result that fell short of statistical significance. Taken together, we strongly agree with Kotzalidis et al. that these results should not prompt physicians to disregard ECT as a treatment option—on the contrary. We also agree that there is evidence supporting that the use of bilateral electrode placement in ECT may have better effect on depression than unilateral electrode placement. However, whether this is also the case in treatment-resistant bipolar depression remains to be seen, and we cannot base treatment recommendation on anecdotal evidence.

Bilateral electrode placement also seems to carry a higher risk for cognitive side effects (1, 2). In our study, follow-up analysis revealed that the unilateral ECT did not show significantly more cognitive side effects than the algorithm-based pharmacological treatment (3). These results further support the use of ECT for treatment-resistant depression. We assume that the relative low remission rate in our study reflects the chronicity and treatment resistance or the patient group included, but electrode placement may be of importance. This shows that more evidence-based knowledge is needed to optimize ECT treatment strategy in bipolar disorder.