The Interaction of Psychologic Stimuli and Pharmacologic Agents on Airway Reactivity in Asthmatic Subjects

Two bronchoactive substances, isoproterenol and carbachol were presented by inhalation to 20 asthmatic subjects in a double blind study. Each drug was given under two conditions: in one case, the subject was told the drug was a bronchodilator; in the other, he was told it was a bronchoconstrictor. The bronchodilator effect of isoproterenol was greater when the subject was told it was a bronchodilator than when told it was a bronchoconstrictor. Similarly, the bronchoconstricting effect of carbachol was greater when the subject was told it was a bronchoconstrictor than when told it was a bronchodilator.