(5) Response to Electroconvulsive Therapy in Treatment Resistant Depression: A Nationwide Register-Based Study

Saturday, August 27, 2022

8:00 AM – 6:00 PM CEST

Location: Hall C

Publication Number: 679

Presenting Author(s)

Adam Nygren, MD
– Psychiatrist, Centre for Pharmacoepidemiology, Karolinska Institutet, Karolinska Institutet, Skarpnack, Sweden

Co-Author(s)

Johan Reutfors
– M.D., Ph.D., associate professor, Centre for Pharmacoepidemiology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden, Sweden
Lena Brandt
– B.Sc., statistician, Centre for Pharmacoepidemiology, Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institute, Stockholm, Sweden, Sweden
Robert Bodén
– M.D., Ph.D., associate professor, Department of Neuroscience, Psychiatry, Uppsala University, Uppsala, Sweden, Sweden
Axel Nordenskjöld
– M.D., Ph.D., associate professor, Ph.D., associate professor, Faculty of Medicine and Health, University Health Care Research Centre, Örebro University, Örebro, Sweden, Sweden
Mikael Tiger
– M.D., Ph.D., Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden, Sweden

Background: Electroconvulsive therapy (ECT) is often considered for patients with treatment resistant depression (TRD), as recommended by guidelines from several countries. However, previous studies have shown inconsistent results regarding the response to ECT in patients with TRD.

Objectives: To assess and compare the response rate of ECT for patients with TRD to that of other patients with depression (i.e. non-TRD) in a large and clinically representative patient sample. We hypothesized that patients with TRD would have a lower ECT response rate than other patients with depression.

Methods: Patients ≥18 years old, treated for a unipolar, non-psychotic depressive episode with at least one ECT session as part of a first-time, index ECT series between Jan. 1 2011 and Dec. 31 2017 were identified from the Swedish National Quality Register for ECT, and individually linked with other population-based registers. Patients with any lifetime diagnosis of bipolar disorder, manic or hypomanic episode, psychotic disorder, or dementia as well as those lacking registration of the primary outcome measure were excluded. Using the Prescribed Drug Register, we classified patients as having TRD if they had initiated a third consecutive trial of antidepressants or add-on medications before starting ECT. Remaining patients were considered to have other depression. The main outcome measure was response to ECT according to the Clinical Global Impressions – Improvement scale (CGI-I) assessed within a week after the ECT series, defined as a CGI-I assessment of ‘much’ or ‘very much improved’. Outcome measures were compared between patients with TRD and with other depression using logistic regression to calculate odds ratios of response and corresponding confidence intervals, adjusting for potential confounders including sociodemographic and clinical covariates.

Results: A total of 4,244 patients were included. Of these, 1,121 patients were classified as TRD (61.2% female, mean age 51.4 years) and 3,123 (54.3 % female, mean age 50.4 years) patients had other depression. The CGI-I response rate after ECT among patients with TRD was 65.9% compared to 75.9% in other patients with depression (adjusted odds ratio 0.64 [95% CI 0.54-0.75]).

Conclusions: A clear majority of patients with TRD as well as patients with other depression responded to ECT, although the response rate was lower in TRD.