Panic attacks and perception of inspiratory resistive loads in chronic obstructive pulmonary disease

Rationale: Panic attacks are common in chronic obstructive pulmonary disease (COPD), and the prevalence of panic disorder is at least 10 times higher than in the general population. In the current study, we examined resistive load perception in patients with COPD with and without panic attacks. Objectives: We tested competing hypotheses, based on conflicting results of earlier studies, that those patients with COPD with panic attacks or panic disorder would show either heightened or blunted perception of dyspnea as the magnitude of inspiratory resistive loads increased. Methods: We compared 20 patients with COPD with panic attacks or panic disorder, 20 patients without panic, and 20 healthy, age-matched subjects using an inspiratory resistive load-testing protocol. Measurements and Main Results: We administered a diagnostic interview for panic attacks and panic disorder. We measured perceived dyspnea in response to increasing inspiratory resistive loads (modified Borg scale) and several respiratory variables. Dyspnea ratings increased linearly for all groups as the size of resistive loads increased. No significant differences were found between groups on the respiratory variables. Patients with COPD with panic attacks or panic disorder rated their level of dyspnea significantly higher than did other subjects. Conclusions: Patients with COPD with panic attacks showed heightened sensitivity to inspiratory loads. The result reinforces the influence of psychological factors on symptom perception in this disease.