Hypersensitivity to 35% carbon dioxide in patients with adult separation anxiety disorder.

BACKGROUND

Adults with panic disorder (PD) and children with separation anxiety disorder (CSAD) show higher reactivity to CO(2). Our hypothesis was patients with adult separation anxiety disorder (ASAD) would show similar hypersensitivity to CO(2). In the present study, we determined whether sensitivity to CO(2) was enhanced in adult patients with separation anxiety disorder with no history of panic attacks.

METHODS

Patients with PD (n=38), adult separation anxiety disorder (ASAD) patients with no history of panic attacks (n=31), and healthy subjects (n=40) underwent a 35% CO(2) inhalation challenge procedure. Baseline and post-inhalation anxiety were assessed with the Acute Panic Inventory, Visual Analog Scale, and Anxiety Sensitivity Index-3 (ASI-3).

RESULTS

As hypothesized the rate of CO(2)-induced panic attacks was significantly greater in PD and ASAD patient groups (55.3% and 51.6% respectively) than healthy comparison group (17.5%). Nine (69.2%) of 13 patients in PD group who have ASAD concurrent with PD had a CO(2)-induced panic attack. ASI-3 total scores were not different between PD and ASAD groups and both were significantly higher than controls. However, anxiety sensitivity did not predict the occurrence of panic attacks.

LIMITATIONS: The researchers were not blind to the diagnosis and there was no placebo arm for comparison. Besides, parameters of respiratory physiology were not evaluated.

CONCLUSION

ASAD was associated with CO(2) hypersensitivity quite similar to PD. This finding partly unfolds the complex relationship of 'CSAD, PD, and CO(2) hypersensitivity' and indicates that CO(2) hypersensitivity and separation anxiety extend together beyond childhood.