Pulmonary function in panic disorder: evidence against the dyspnea-fear theory

The present study addresses the hypothesis consistent with the dyspnea-fear theory of panic, that in a subgroup of panic patients a non-pathological pulmonary obstructive component may induce dyspnea, dyspneic fear and, ultimately, panic. In 38 patients who met DSM-III-R criteria for panic disorder, pulmonary function was assessed and various measurements for panic symptoms and concomitant psychopathology were collected. In comparison to patients with a high Forced Expiratory Flow at 50% (FEF 50%), low FEF 50% patients demonstrated significantly lower levels of Forced Expiratory Volume (first second) and Peak Expiratory Flow and significantly lower FEV1/FVC ratios. None of the differences on psychological measurements for symptom severity between low and high FEF 50% patients proved to be significant. Moreover, FEF 50% scores and FEV1/FVC ratios were not correlated to any of the measures for panic or associated psychopathology. It is concluded that the existence of a distinct subgroup of panic patients with signs of actual airway obstruction leading to uncontrollable dyspnea and fear of suffocation remains questionable.