Is there a specific relationship between asthma and panic disorder?

The objective of the present study was three-fold: (1) to assess the prevalence of PD in asthmatic patients in comparison with non-asthmatic patients; (2) to investigate possible differences in pulmonary function and anxiety symptomatology between asthmatic patients with PD and those without; and (3) to evaluate possible differences in symptom perception during histamine-induced bronchoconstriction between asthmatic patients with PD versus asthmatic controls without PD matched for age, sex and bronchial responsiveness to histamine (PC20). The study was performed on 123 consecutive patients referred to the lung function laboratory of a university hospital for a histamine challenge test. Firstly, baseline measures for FEV1, anxiety (ADIS-R, ACQ, BSQ, and STAI) and depression (SDS) were collected. Subsequently, before and during induced bronchoconstriction FEV1, perceived breathlessness (Borg scale), subjective anxiety (SUDS), and somatic panic symptoms (PAQ) were assessed. The prevalence of PD in asthmatic patients, although higher than in the general population, was very similar to the rate observed in non-asthmatic patients. Baseline level of FEV1 and bronchial responsiveness to histamine (PC20) were also not significantly different between asthmatic patients with and without PD. Moreover, in comparison with matched controls, PD cases reported significantly higher levels of perceived breathlessness during induced bronchoconstriction, although their mean fall in FEV1 was very comparable. It is concluded that the higher prevalence of PD in asthma is non-specific and probably due to selection bias.