Memory loss from shock therapy tied to technique
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Memory loss due to electroconvulsive therapy (ECT), commonly known as electroshock therapy, may to a large extent be associated with how the treatment is administered, according to a study of patients referred to one of seven hospitals in the New York metropolitan area for ECT.
Despite ongoing controversy, there has never been a large-scale study of the cognitive effects of ECT, Dr. Harold A. Sackeim of New York State Psychiatric Institute, New York, and colleagues point out in the journal Neuropsychopharmacology.
Some researchers have concluded that substantial amnesia is unavoidable; others say improvements in ECT have made cognitive impairments only temporary.
Sackeim’s team studied the long-term cognitive outcomes of 347 patients with severe depression treated at three community general hospitals, two university hospitals, or two private psychiatric hospitals. All of the patients were evaluated at least one time after having electroshock therapy.
Cognitive outcomes at the seven sites differed significantly immediately after and 6 months after ECT. This was true even after taking patient characteristics into consideration.
Differences in ECT technique, say the investigators, largely accounted for these differences.
For example, electrode placement had marked cognitive effects. Placing electrodes on both sides of the head (bilateral ECT) resulted in more severe and persisting amnesia than placing them only on the right side (right unilateral ECT).
Compared with healthy controls, patients treated exclusively with bilateral ECT showed 3.4 times the memory loss immediately after ECT and 2.8 times the memory loss 6 months after ECT, the authors found.
Greater cognitive effects were also associated with older age, lower intellectual function and female sex.
Sackeim told Reuters Health that “ECT, done under less than optimal conditions, has demonstrable long-term effects on memory.”
However, he added, “it is also the most effective short-term antidepressant and its adverse cognitive effects can be substantially reduced, if not eliminated, by adoption of advances in technique.”
SOURCE: Neuropsychopharmacology, January 2007.
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