HEMODYNAMIC-RESPONSE TO RESPIRATORY CHALLENGES IN PANIC DISORDER

This study compares the hemodynamic response to panic disorder subject s with that of normal controls during respiratory challenges. Panic pa tients meeting DSM-IIIR criteria for panic disorder and normal control s were challenged with room air hyperventilation, 5% CO2 breathing, an d 7% CO2 breathing. Measurements of pulse and blood pressure were take n at resting baseline and before and at the end of each respiratory ch allenge. Panic attack to each challenge was determined by using raters blinded to subject diagnosis and each subject's self-rating of panic. Significantly larger systolic and diastolic blood pressure increases were found in patients who panicked with room air hyperventilation tha n nonpanicking patients or normal controls. No significant blood press ure differences were found with 7% or 5% CO2 challenges, but higher pu lse rates were found in the patient group. It may be possible that pan ic with room air hyperventilation causes a significant increase in sys tolic and diastolic blood pressure, or that a subgroup of panic disord er patients has a hyperactive vascular response to hypocapnia. These p atients panic with room air hyperventilation and develop greater vasoc onstriction and/or increased blood pressure response. (C) 1998 Elsevie r Science Inc.