Does suggestibility modify acute reactions to passive cigarette smoke exposure?

The influence of suggestibility on responses to passive cigarette smoke exposure was tested in a group of 24 healthy adult nonasthmatic nonsmokers and 16 asthmatic nonsmokers. Sixty-five-min exposures to air and to moderate (17 ppm carbon monoxide) and heavy (31 ppm carbon monoxide) concentrations of machine-produced cigarette smoke were carried out according to a design that permitted all six permutations of the three treatments to be equally represented. Nonasthmatic subjects exercised intermittently at an intensity inducing a respiratory ventilation of 43.6 liters/min, while asthmatic individuals were at rest, in a 14.6-m3 chamber; all viewed a bank of burning cigarettes during each exposure. Significant dose-response relationships were observed for reported symptoms, deterioration of pulmonary function, increase in nasal airflow resistance, and increase of carboxyhemoglobin levels. These findings could reflect either a pure physiological response, or an interaction between physiological and psychological responses. For asthmatics, correlations between pulmonary function responses and baseline measures of suggestibility showed 5/45 (11%) significant correlations (P less than 0.05) for both the ratio of saline diluent/air FEV1 during methacholine inhalation challenge and an index derived from the Minnesota Multiphasic Personality Inventory (MMPI), while no significant correlations were shown with the James "locus of control" test. Nonasthmatics showed 4/45 (9%) significant correlations for both the James test and the MMPI index, and 1/45 (2%) for the ratio of saline diluent/air FEV1. It is concluded that while suggestibility may augment physiological responses to passive smoking, any effect is relatively weak.