ECT Does Not Increase the Risk for Dementia in Those With Affective Disorders

Electroconvulsive therapy (ECT) may not be associated with an increased risk for dementia in patients with affective disorders after corrections for the potential effects of patient selection have been made, according to the results of a Danish cohort study published in Lancet Psychiatry.

Merete Osler, DMSc, from the Center for Clinical Research and Prevention, Bispebjerg and Frederiksberg Hospitals, Frederiksberg, Denmark, and the Department of Public Health, University of Copenhagen, Copenhagen, Denmark, and colleagues analyzed data collected in the Danish National Patient Registry of patients aged 10 years and older with a first-time hospital contact for an affective disorder from January 1, 2005, through December 31, 2015.

They retrieved information on all ECT procedures received by patients and followed-up patients for incidental dementia until October 31, 2016. Using Cox regression analyses with multiple adjustments and propensity-score matching on sociodemographic and clinical variables, they examined the association between ECT and dementia.

A total of 168,015 patients were included in the study, 5901 (3.5%) of whom had had at least 1 ECT. Over the course of the median 4- to 9-year follow-up (872,874 person-years), 0.1% of patients aged 10 to 49 years, 2.7% of those aged 50 to 69 years, and 12.5% of those aged 70 to 108 years developed dementia.

Among the 5901 patients treated with ECT, 3.6% developed dementia, whereas 3.1% of patients not treated with ECT developed dementia. The dementia incidences were 70.4 per 10,000 person-years for those treated with ECT compared with 59.2 per 10,000 person-years in those not treated.

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In patients younger than 50 years and those aged 50 to 69 years, ECT was not associated with an increased risk for dementia compared with age-matched patients who had not undergone ECT (age-adjusted hazard ratio [HR], 1.51; P =.32).

In patients who were 70 years of age and older, ECT was associated with a decreased rate of dementia (HR, 0.68; P <.0001), which was, however, diminished with propensity-score matching (HR, 0.77; P =.062). When competing mortality was accounted for in the supplementary analyses, ECT was not significantly associated with ECT (subdistribution HR, 0.98; P =.24).

Given these findings, the authors argue for the continued use of ECT in patients with severe episodes of mood disorders, including elderly patients.


Osler M, Rozing MP, Christensen GT, Andersen PK, Jorgensen MB. Electroconvulsive therapy and risk of dementia in patients with affective disorders: a cohort study. Lancet Psychiatry. 2018;5(4):348-356.