The Cognitive Effects of ECT: Tolerability Versus Safety

March 13, 2013
Volume 30, Issue 3

In addition to having an excellent safety profile, ECT is widely acknowledged to be the most effective acute antidepressant treatment.

Concern about cognitive effects is the main reason ECT is not more widely prescribed for severe depression. ECT is mistakenly considered a “last resort” treatment, one that appears far down the list in treatment algorithms, if it is considered at all.1

This delay or failure to appropriately prescribe ECT results in seriously ill patients remaining depressed for prolonged periods; sometimes it results in suicides that could have been prevented or death from medical causes.2

The concern about cognitive effects is exaggerated; most ECT patients experience minor cognitive impairment, much of which is temporary. The restricted use of ECT because of overstated fears of memory loss is a significant public health problem. Part of this problem stems from the fact that the cognitive effects of ECT are considered a safety issue. I suggest that it is more appropriate to consider the cognitive impact of ECT a tolerability issue.

In medicine, safety almost always refers to risk (or lack thereof) of physical injury or death. When we think of the safety of a medical or surgical procedure, we consider first the mortality rate then the rate of complications, such as infection, disfigurement, or ongoing pain. All surgical procedures result in temporary postoperative pain, yet we never consider this part of the safety profile of the procedure. Likewise, with chemotherapy, we think of safety as the risk of blood dyscrasias and immunosuppression; temporary hair loss and “chemo brain,” are unpleasant adverse effects, but not typically considered “safety” issues. This may have to do with the general acceptance of the idea that cancer is a life-threatening illness and the risk to benefit ratio clearly favors accepting bothersome, but nonserious, adverse effects in return for extended life.

Semkovska and McLoughlin3 performed a systematic review and meta-analysis of 84 studies (N = 2981) that used standardized tests to assess cognition in ECT patients. They concluded:

. . . cognitive abnormalities associated with ECT are mainly limited to the first 3 days posttreatment. Pretreatment functioning levels are subsequently recovered. After 15 days, processing speed, working memory, anterograde memory, and some aspects of executive function improve beyond baseline levels.

While some patients experience more substantial memory impairments, this is not typical. The most commonly reported memory effect, retrograde amnesia, represents the loss of certain past memories, a static (unless the memories return, in which case it is improving) content problem, not an ongoing problem of memory functioning.

MDD in its most severe forms, those for which ECT is appropriate, is a life-threatening illness. The lifetime suicide risk for patients with major mood disorders is in the 15% range.4 Unfortunately, the public has a very fuzzy idea of what serious depression is, particularly compared with clear and terrifying views of what cancer, diabetes, and heart disease are. It is because depression is not considered a life-threatening illness on a par with cancer or heart disease that a double standard of what constitutes safety exists.

ECT is considered the safest procedure performed under general anesthesia. It has an estimated mortality rate of 1 in 10,000 patients.5 A recent study of ECT mortality found no deaths in 73,440 treatments performed in Veterans Administration hospitals between 1999 and 2010 as well as a remarkably small number of significant adverse events.6

In addition to having an excellent safety profile, ECT is widely acknowledged to be the most effective acute antidepressant treatment. Remission/response rates in ECT clinical trials are typically in the 60% to 80% range, far higher than comparable rates for antidepressant medications.7-9 ECT also works more quickly than antidepressant medications, with improvement often evident within 1 week of treatment.10

During the recent FDA Neurological Devices Panel advisory meeting, the discussion of the safety of ECT was almost totally focused on cognition. Unfortunately, there was even the inference that memory effects of ECT might somehow be equated to a form of “brain damage.” This is an unfounded and radical view, one that suggests a misunderstanding of the scientific literature on ECT and cognition, the modern practice of ECT, and brain physiology. Such a view may also have implications for academic medical center institutional review boards (IRBs) when they are considering ECT research protocols. IRB panels often include personnel who have no familiarity with ECT; therefore ECT protocols are subject to particular scrutiny of informed consent procedures, and warnings about cognitive impairment are often the focus.

We should strive to enhance the tolerability of ECT while maintaining its remarkable safety and efficacy profiles. Great strides are being made: the increasing implementation of a very cognitively benign form of ECT, right unilateral ultrabrief pulse ECT, is one such advancement.11 The cognitive impact of ECT, particularly retrograde amnesia, should be considered an important, but not overriding, tolerability issue. To consider it a safety issue is a distortion of the generally accepted medical understanding of what constitutes safety; it is also likely a result of the long-standing prejudice against ECT and the failure to understand the seriousness of severe major depression.



1. Beale MD, Kellner CH. ECT in treatment algorithms: no need to save the best for last. J ECT. 2000;16:1-2.

2. Belaizi M, Yahia A, Mehssani J, et al. Acute catatonia: questions, diagnosis and prognostics, and the place of atypical antipsychotics [in French]. Encephale. 2012 Oct 11; [Epub ahead of print].

3. Semkovska M, McLoughlin DM. Objective cognitive performance associated with electroconvulsive therapy for depression: a systematic review and meta-analysis. Biol Psychiatry. 2010;68:568-577.

4. Guze SB, Robins E. Suicide and primary affective disorders. Br J Psychiatry. 1970;117:437-438.

5. American Psychiatric Association. The Practice of Electroconvulsive Therapy: Recommendations for Treatment, Training, and Privileging. 2nd ed. Washington, DC: American Psychiatric Association; 2001.

6. Watts BV, Groft A, Bagian JP, Mills PD. An examination of mortality and other adverse events related to electroconvulsive therapy using a national adverse event report system. J ECT. 2011;27:105-108.

7. Janicak PG, Davis JM, Gibbons RD, et al. Efficacy of ECT: a meta-analysis. Am J Psychiatry. 1985;142:>297-302.

8. Prudic J, Haskett RF, Mulsant B, et al. Resistance to antidepressant medications and short-term clinical response to ECT. Am J Psychiatry. 1996;153:985-992.

9. Kellner CH, Knapp RG, Petrides G, et al. Continuation electroconvulsive therapy vs pharmacotherapy for relapse prevention in major depression: a multisite study from the Consortium for Research in Electroconvulsive Therapy (CORE). Arch Gen Psychiatry. 2006;63:1337-1344.

10. Husain MM, Rush AJ, Fink M, et al. Speed of response and remission in major depressive disorder with acute electroconvulsive therapy (ECT): a Consortium for Research in ECT (CORE) report. J Clin Psychiatry. 2004;65:485-491.

11. Sienaert P, Vansteelandt K, Demyttenaere K, Peuskens J. Randomized comparison of ultra-brief bifrontal and unilateral electroconvulsive therapy for major depression: cognitive side-effects. J Affect Disord. 2010;122:60-67yes.