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February 1989

ß-Blockade and Mental Performance

Arch Intern Med. 1989;149(2):475. doi:10.1001/archinte.1989.00390020156046

To the Editor.—The study by Gengo et al1 that examined the effects of β-blockers on mental performance in older hypertensive patients has several inadequacies in study design in addition to those mentioned in the accompanying editorial.2

First, the previous drug therapy of the study group requires further evaluation. Some of the subjects, perhaps a majority, had been taking β-blockers prior to the study. These patients may have been a select group with a proved tolerance to β-blockers, and, therefore, may have been, a priori, less likely to develop central nervous system side effects from the study drugs. Thus, the number of patients receiving β-blockers, and the nature of these agents, should have been reported.

Second, although the investigators were blinded as to the sequence of active drug periods, they were aware of when the patients were taking placebo and when they were taking active drugs. Since knowledge

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