Response to 5% Carbon Dioxide in Children and Adolescents: Relationship to Panic Disorder in Parents and Anxiety Disorders in Subjects

Background: Carbon dioxide (CO2) sensitivity is postulatedtobeafamilialriskmarkerofpanicdisorder(PD). Exaggerated responses to CO2 inhalation have been reported in adults with PD and their unaffected adult relatives, as well as in clinic-referred children with anxiety disorders. Objective:Totestinafamily-baseddesignwhetherCO2 hypersensitivity is a familial risk marker for PD and associated with current anxiety disorders in children and adolescents. Setting and Participants: One hundred forty-two offspring (aged 9-19 years) of parents with PD, major depressive disorder, or no disorder. Forty-five (32%) had a current anxiety disorder, excluding specific phobia. Design and Main Outcome Measures: Parents and offspring received diagnostic assessments. Offspring underwent5%CO2inhalationathome.Panicsymptomsand panic attacks were rated with the Acute Panic Inventory at baseline, while anticipating CO2 delivery (“threat”), and during CO2 inhalation. Respiratory rate and volume were measured with spirometry. Results:NogroupdifferenceswerefoundinAcutePanic Inventoryratingsatbaselineorinrespiratorymeasuresduring threat. Risk for PD was not associated with CO2sensitivity(panicsymptomsandrespiratoryphysiologicresponse). DuringCO2inhalation,offspringwithanxietydisorders,relativetooffspringwithoutanxietydisorders,experiencedsignificantlymorepanicsymptomsandpanicattacks,aswell aselevatedrespiratoryrates.Duringthreat,panicsymptoms weresignificantlyandindependentlyassociatedwithboth parental PD and offspring anxiety disorders. Conclusions: No support was obtained for CO2 hypersensitivityasafamilialriskmarkerforPDinchildrenand adolescents. Links between childhood anxiety disordersandCO2sensitivitywerereplicated.Familialriskfor PD in children and adolescents may be associated with vulnerability to anticipatory anxiety. Arch Gen Psychiatry. 2005;62:73-80