Electroconvulsive therapy, or ECT, is one of the most effective treatments available for severe depression, but many people considering it worry about its effect on memory and thinking. A retrospective study looked closely at cognitive outcomes in 90 inpatients, averaging 49 years of age, who received a course of ECT, on average ten sessions, for treatment-resistant depression.
Using a standard measure of overall thinking ability, the study found no significant change in global cognition after treatment. A small minority, three patients, showed a meaningful drop on this measure. Looking at a wider battery of cognitive tests, most showed no change. Two areas of thinking, visual learning and reaction time, actually improved. One area, verbal learning, showed a statistically significant decline. Older patients and those who received higher doses of stimulation had worse outcomes in some of these areas. Depression itself improved significantly with ECT, and this improvement was not linked to how cognition changed.
Overall, the study did not find major cognitive changes from this course of ECT, though the effects were mixed and, in one area, negative. ECT is prescribed and delivered by psychiatrists; if you are considering it, discuss the risks and benefits with your treating psychiatrist, and a psychologist can support you alongside that care.
What the study looked at
Electroconvulsive therapy (ECT) is recognised as one of the most effective treatments for severe, treatment-resistant depression, but concern about its effect on memory and thinking remains one of the most common reasons people hesitate to consider it. This retrospective study set out to examine both the cognitive effects and the antidepressant effectiveness of ECT in a real-world clinical sample, rather than a tightly controlled trial.
The study included 90 inpatients with treatment-resistant unipolar or bipolar depression, with an average age of 49 years. Patients received an average of ten ECT treatments, using either unilateral or bitemporal electrode placement, and completed an extensive battery of psychological tests before and after treatment. The two main outcomes were depression severity, measured with the Hamilton Depression Rating Scale (HAMD), and global cognitive function, measured with the Mini-Mental State Examination (MMSE).
What it found
There was no statistically significant change in MMSE scores from before to after treatment, indicating that ECT did not have a negative effect on global cognition in this sample overall. A small number of patients, three out of ninety, did show a meaningful decline of five or more points on this measure.
Looking beyond this single global measure to a wider battery of cognitive tests, the picture was mixed. Most tests showed no significant difference before and after treatment. Two specific domains, visual learning and motor reaction time, showed statistically significant improvement. One domain, verbal learning, showed a statistically significant decline. Effect sizes across these changes were described as small. Older age and higher doses of electrical stimulation were linked to worse outcomes in some cognitive domains.
Depression itself improved significantly with ECT, as measured by a clear drop in HAMD scores. Importantly, the degree of improvement in depressive symptoms was not associated with how a person's cognition changed, meaning cognitive changes and antidepressant response appeared to occur independently of one another.
Why it matters
For people considering ECT, or for those supporting a family member through the decision, cognitive side effects are often the central concern. This study's findings are broadly reassuring on global cognition, with no major overall decline observed, while still being honest about a specific decline in verbal learning and the fact that a small subgroup did experience a more meaningful drop. This kind of detailed, mixed picture is more useful for informed decision-making than a simple reassurance that ECT does not affect memory at all.
Its limits
This was a retrospective study of real-world clinical practice, not a randomised controlled trial, and the authors note the absence of any assessment of retrograde memory, meaning memory for events before treatment, as a specific limitation. The findings apply to a specific sample of adults with treatment-resistant depression receiving a defined course of ECT, and individual experiences can vary.
ECT is a medical treatment, prescribed, supervised and delivered by psychiatrists, typically within a hospital setting. It falls outside psychological practice. If you or someone you care about is considering ECT, the right first step is a detailed conversation with a treating psychiatrist about individual risks and benefits. A psychologist can provide valuable support alongside that medical care, including help preparing for treatment and adjusting afterwards.