Carbon Dioxide Hypersensitivity in Separation-Anxious Offspring of Parents with Panic Disorder

Background Similar patterns of vulnerability to carbon dioxide (CO 2 ) inhalation have been reported in adults with panic disorder (PD) and children with separation anxiety disorder (SAD), suggesting a link between the adult and child conditions. This study examines the influence of familial risk for PD on CO 2 responses in children with SAD. We hypothesized that offspring with SAD of parents with PD would have distinct CO 2 responses. Methods Two hundred twelve 9- to 20-year-old offspring of parents with or without PD were exposed to maintained 5% CO 2 inhalation in the participants' homes. Anxiety symptoms, panic attacks, and respiratory physiology (respiratory frequency and tidal volume) were monitored during baseline and 15-min maintained CO 2 breathing. Results As hypothesized, significant offspring SAD × parent PD interactions were obtained for anxiety symptoms, respiratory frequency, tidal volume, and a panting index during CO 2 inhalation. Offspring with both SAD and parental PD exhibited more anxiety symptoms at termination of 5% CO 2 breathing than the other offspring groups and had the most extreme values on measures of respiratory physiology. Conclusions Youth with both SAD and parental PD have respiratory responses to CO 2 similar to adult PD. They might be a subtype of SAD at particularly high risk for adult PD.