Negative affect, respiratory reactivity, and somatic complaints in a CO2 enriched air inhalation paradigm

Subjects scoring high on negative affectivity (NA) are known to report more psychosomatic complaints than subjects scoring low. According to the symptom perception hypothesis, high NA subjects attend more to somatic sensations and interpret these as more threatening. We investigated the relationship between NA and psychosomatic complaints in a group of high and low NA subjects (N = 72) in, (a) a questionnaire study, and (b) in a laboratory setting. The latter involved the inhalation of three different gas mixtures (room air, 5.5% and 7.5% CO2-enriched air) while respiratory responses were registered. Subjective complaints were measured after each trial. High NA subjects reported more complaints than low NA subjects in the questionnaire study. However, NA had no main effects on complaints in the laboratory study and did not interact with the effects of gas mixture on complaints. During room air trials, NA correlated only with general arousal complaints when a strong respiratory challenge had not been given before. The pattern of results suggests that experimental inductions of complaints may largely wipe out NA-related differences in attentional/interpretative processes that may mediate the NA complaints link.