Retrospective Study of Unipolar Depression Treated with ECT

From the Q-ECT, we identified patients who were aged ≥18 years and had been treated for a unipolar, non-psychotic depressive episode (ICD-10²⁰ codes of F32 for depressive episode or F33 for recurrent depression, excluding F32.3 and F33.3 for psychotic depression) with at least one ECT session as part of a first-time, index ECT series in Sweden between 1 January 2011 and 31 December 2017 (Fig. 1). When registration of treatment indication was lacking or unclear in the Q-ECT, diagnostic information was added from the NPR. This resulted in 6615 eligible patients with a diagnosis of depression treated with ECT. Patients with any registered lifetime diagnosis of bipolar disorder, manic or hypomanic episode, psychotic disorder or dementia were excluded, as were patients lacking data on the primary outcome measure (CGI-I score). After these exclusions, a total of 4244 patients were included in the final analyses.
Fig. 1

Flow chart of study inclusion. CGI-I, Clinical Global Impressions – Improvement Scale; CGI-S, Clinical Global Impressions – Severity Scale; ECT, electroconvulsive therapy; Q-ECT Swedish National Quality Register for ECT; NPR, Swedish National Patient Register.