Panic disorder needs to be considered

EDITOR—Thomas et al report an appreciable prevalence of dysfunctional breathing in adults with asthma and discuss the scope for wider use of breathing therapy.1 Neither Thomas et al nor Keeley and Osman in their editorial2 consider whether such symptoms might occur equally often in the normal population or represent panic attacks and panic disorder, well defined entities common in otherwise healthy people. Without a control group their study is incapable of identifying the prevalence of dysfunctional breathing associated specifically with asthma.

Dysfunctional breathing and the hyperventilation syndrome are by no means the same as panic syndromes, but overlap between them may be considerable. Thomas et al acknowledge limitations of the Nijmegen questionnaire.3 This instrument cannot differentiate the “chimeric” hyperventilation syndrome from panic attacks and panic disorder. The 16 items in the Nijmegen questionnaire include “anxiety,” “feeling tense,” and nine of the 13 panic attack symptoms listed in the Diagnostic and Statistical Manual of Mental Disorders, third edition, revised (DSM-III-R). The questionnaire was not defined to attempt to make this distinction. A 23% lifetime prevalence of spontaneous panic attacks has been reported in patients with asthma.4 This figure is not dissimilar to the 29% of asthmatic patients labelled by Thomas et al as having experienced dysfunctional breathing and again suggests appreciable overlap. The lifetime prevalence of asthmatics meeting DSM-III-R criteria for panic disorder in the same study …