Differential carbon dioxide sensitivity in childhood anxiety disorders andnonill comparison group

Background: To examine the relationship between respiratory regulation and childhood anxiety disorders, this study considered the relationship between anxiety disorders and symptoms during carbon dioxide (CO2) exposure, CO2 s ensitivity in specific childhood anxiety disorders, and the relationship be tween symptomatic and physiological. responses to CO2. Methods: Following procedures established in adults, 104 children (aged 9-1 7 years), including 25 from a previous study, underwent 5% CO2 inhalation. The sample included 57 probands with an anxiety disorder (social phobia, ge neralized anxiety disorder, separation anxiety disorder, and panic disorder ) and 47 nonill comparison subjects. Symptoms of anxiety were assessed befo re, during, and after CO2 inhalation. Results: All children tolerated the procedure well, experiencing transient or no increases in anxiety symptoms. Children with an anxiety disorder, par ticularly separation anxiety disorder, exhibited greater changes in somatic symptoms during inhalation of CO2-enriched air, relative to the comparison group. During CO2 inhalation, symptom ratings were positively correlated w ith respiratory rate increases, as well as with levels of tidal volume, min ute ventilation, end-tidal CO2, and irregularity in respiratory rate during room-air breathing. Conclusions: Childhood anxiety disorders, particularly separation anxiety d isorder, are associated with CO2 hypersensitivity, as defined by symptom re ports. Carbon dioxide hypersensitivity is associated with physiological cha nges similar to those found in panic disorder. These and other data suggest that certain childhood anxiety disorders may share pathophysiological feat ures with adult panic disorder.