Respiratory airway changes in response to suggestion in normal individuals.

Thirty normal individuals were told they were inhaling a substance that would either cause breathing difficulty (N = 15) or not affect breathing (N = 15). Total respiratory resistance was measured prior to and during inhalation. In reality, the subjects inhaled no substance; inhalation consisted of breathing normally into a respiratory resistance recorder. Individuals who received the former suggestion exhibited increased total respiratory resistance during inhalation, whereas individuals who received the latter suggestion did not. These observations demonstrated that the ability of suggestion to affect the respiratory airway is not limited to asthmatic individuals.