Hyperventilation symptoms and their relationship to panic.

Abstract

Symptom overlap between the Hyperventilation Syndrome (HVS) and Panic Disorder (PD) has been noted by many investigators; however, the reasons for this association are unclear. By following 50 college subjects (36 female and 14 male) who displayed extremely high rates of hyperventilation symptoms over four-week to nine-month intervals, symptom stability patterns as well as the relationship to panic attacks were examined. Rates of overlap between hyperventilation symptoms and panic attacks was 66% in the current sample. Furthermore, 4 of 50 (8%) of panic-free subjects developed panic attacks during the course of the investigation. Although the frequency of hyperventilation symptoms decreased over time for most subjects, many individuals continued to be symptomatic over time. One potential mechanism of association between hyperventilation and panic (i.e., focus on either somatic or somatic plus cognitive symptoms of hyperventilation) was not supported, and several personality variables (repression and anxiety sensitivity) were not found to influence the relationship between hyperventilation and panic. Finally, measurement issues related to a hyperventilation symptom questionnaire were addressed. The two-week test-retest reliability was .79. Evaluation of the validity of the HVQ by assessing end-tidal CO₂ levels of 30 subjects resulted in no significant differences between high and low scorers. Implications of the present findings are discussed in light of current theoretical models of the relationship between HVS and PD.