The course of depressive symptoms in unipolar depressive disorder during electroconvulsive therapy: A latent class analysis

Background: Research examining the course of depressive symptoms during electroconvulsive therapy (ECT) is relatively scarce. Objective: To classify patients according to the course of their depressive symptoms while receiving ECT. Methods: The sample consisted of 156 consecutive patients receiving ECT for unipolar depressive disorder. Depressive symptoms were measured weekly with the Montgomery-Asberg Depression Rating Scale. Latent class analysis was applied to identify distinct trajectories of symptom improvement. Results: We identified five classes of different trajectories (improvement rates) of depressive symptoms, i.e. fast improvement (39 patients), intermediate improvement (47 patients), slow improvement (30 patients), slow improvement with delayed onset (18 patients), and finally a trajectory with no improvement (20 patients). The course of depressive symptoms at the end of the treatment within the trajectories of intermediate improvement, slow improvement and slow improvement with delayed onset, was still improving and did not achieve a plateau. Conclusion: The different courses of depressive symptoms during ECT probably contribute to mixed results of prediction studies of ECT outcome. Data suggest that for a large group of patients no optimal clinical endpoint can be identified, other than full remission or no improvement at all, to discontinue ECT. (C) 2009 Elsevier B.V. All rights reserved.