Respiratory symptoms and panic in the National Comorbidity Survey: a test of Klein's suffocation false alarm theory.

According to suffocation false alarm theory (Arch. Gen. Psychiatry 50 (1993) 31), respiratory symptoms are the symptoms that best distinguish the panic attacks of individuals with panic disorder (PD) from those of individuals without PD. Using National Comorbidity Survey data from those 609 respondents who had lifetime histories of panic attacks or PD, we tested this prediction. Neither respiratory symptom (smothering; dyspnea) strongly differentiated between respondents with PD and those with only panic attacks. Respiratory symptom endorsement was unrelated to PD when the number of other symptoms endorsed was controlled; furthermore, respiratory symptoms had slight effect sizes and were not included in a multivariate context. In contrast, fear of dying had the largest effect size, an association with PD that persisted after control for other symptom endorsement, and a continuing importance in multivariate analyses. Strikingly, panic attack respondents who reported having had only one panic attack were as likely as PD respondents to report respiratory symptoms during panic. These findings, although based on retrospective self-report and thus subject to recall bias, are inconsistent with the hypothesis that respiratory symptoms during panic have diagnostic significance.