Finally, the choice of the seizure threshold as the variable on which to base ECT dosage is arbitrary; more useful measures may exist. (4) An individual physiological response, such as the degree of electroencephalographic postictal suppression (ie, a postictal suppression threshold), should provide a more rational guide to stimulus dosage because, unlike the seizure threshold, the degree of postictal suppression has been shown to be related to the antidepressant response.5-7 Other readily obtainable physiological measures (eg, heart rate) are also candidates for thresholds against which to titrate the stimulus dose. (8)

Even when administered at high dosages, unilateral ECT seems to retain important cognitive advantages over bilateral ECT. To date, unilateral ECT regardless of dosage has not been demonstrated to induce persistent amnesia, whereas studies have found detectable retrograde amnesia 2 to 6 months after bilateral ECT. However, because the 2.5 times seizure threshold dosing used in the study by Sackeim et al (1) is higher than required for the usual and expected antidepressant benefit from bilateral ECT, (9) it probably exaggerated the cognitive differences between the 2 methods.

It is time for the Food and Drug Administration to act. The aforementioned dosage considerations are moot for US psychiatrists and their patients in that present Food and Drug Administration regulations do not permit the sale in this country of ECT devices capable of administering, for example, 6 times seizure threshold dosing to all patients (high-dose ECT devices have been available outside the United States for many years). Unless more efficient forms of stimulation (eg, shorter pulse width, longer-duration stimuli) are proven effective at dosages within the range of presently available ECT devices, patients in the United States will be excluded from receiving the most efficacious forms of unilateral ECT. (4, 10)

Author/Article Information

Richard Abrams, MD
Department of Psychiatry and Behavioral Sciences
Chicago Medical School
3333 Green Bay Rd
North Chicago, IL 60064

Dr Abrams is director of Somatics Inc, Lake Bluff, Ill, the manufacturer of the Thymatron Electroconvulsive Therapy device.

I thank Max Fink, MD, and Conrad M. Swartz, PhD, MD, for providing helpful critiques of earlier drafts of this commentary.

next: Voices From Within: A Study of ECT and Patient Perceptions - Abstract

REFERENCES

1. Sackeim HA, Prudic J, Devanand DP, Nobler MS, Lisanby SH, Peyser S, Fitzsimons L, Moody BJ, Clark J. A prospective, randomized, double-blind comparison of bilateral and right unilateral electroconvulsive therapy at different stimulus intensities. Arch Gen Psychiatry. 2000;57:425-434.

2. McCall WV, Reboussin DM, Weiner RD, Sackeim HA. Titrated moderately suprathreshold vs fixed high-dose right unilateral electroconvulsive therapy: acute antidepressant and cognitive effects. Arch Gen Psychiatry. 2000;57:438-444.

3. Abrams R, Swartz CM, Vedak C. Antidepressant effects of high-dose right unilateral electroconvulsive therapy. Arch Gen Psychiatry. 1991;48:746-748.

4. Abrams R. Electroconvulsive Therapy. 3rd ed. New York, NY: Oxford University Press; 1997.

5. Krystal AD, Weiner RD, Gassert D, McCall WV, Coffey CE, Sibert T, Holsinger T. The relative ability of three ictal EEG frequency bands to differentiate ECT seizures on the basis of electrode placement, stimulus intensity, and therapeutic response. Convuls Ther. 1996;12:13-24.

6. Nobler MS, Sackeim HA, Solomou M, Luber B, Devanand DP, Prudic J. EEG manifestations during ECT: effects of electrode placement and stimulus intensity. Biol Psychiatry. 1993;34:321-330. MEDLINE

7. Petrides G, Kellner C, Knapp R, Rummans T, O'Connor K, Hussain M, Fink M, Rush AJ, Rasmussen K, Beale M, Bernstein H, Biggs M, Mueller M, Zhao W. Can ictal EEG indices predict response to ECT? Presented as a poster at: the National Clinical Drug Evaluation Unit meeting; May 30-June 2, 2000; Boca Raton, Fla.

8. Swartz CM. Disconnection of EEG, motoric, and cardiac evidence of ECT seizure. Convuls Ther. 1996;12:25-30.

9. Sackeim HA, Prudic J, Devanand DP, Kiersky JE, Fitzsimons L, Moody BJ, McElhiney MC, Coleman EA, Settembrino JM. Effects of stimulus intensity and electrode placement on the efficacy and cognitive effects of electroconvulsive therapy. N Engl J Med. 1993;328:839-846.

10. Sackeim HA. Are ECT devices underpowered? Convuls Ther. 1991;7:233-236.

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