Experimental affective symptoms in panic disorder patients.

OBJECTIVE

To date, carbon dioxide (CO2) challenge tests in panic disorder (PD) patients have focused on anxiety as the sole outcome measure. This study assesses a broader range of symptoms in patients with PD.

METHOD: We administered a gas mixture of 35% CO2 and 65% oxygen (O2) to 25 patients with PD. Nine patients met the criteria for a comorbid major depressive disorder (MDD), and 16 did not. We assessed not only subjects' symptoms of anxiety but also their symptoms of depression and aggression.

RESULTS

Baseline ratings did not differ across the 2 subgroups. Postchallenge ratings were higher for PD and MDD patients on all the assessed affective symptoms, except for specific panic symptoms.

CONCLUSION

These findings suggest that, in addition to anxiety, CO2 challenge induces depressive and aggressive symptoms, specifically in PD patients with comorbid depression.