Panic disorder: the role of the balance system

Experimental evidences suggest that Panic Disorder (PD) is characterized by abnormalities in respiratory and vestibular functions. We studied balance system function in patients with PD and its relationships with CO, reactivi ty and clinical characteristics. Nineteen patients with PD with/without ago raphobia underwent static posturography and the 35% CO2 challenge. The seve rity of clinical symptomatology was measured by standardized psychometric s cales. Patients were free of psychotropic medications during the 2 weeks be fore tile Study. Different investigators blind to each other carried out th e CO, challenge, static posturography and clinical assessment. Nineteen age and sex-matched healthy controls underwent static posturography. Body sway velocity and length were significantly higher in panic patients than in co ntrols and patients showed high percentages of abnormal scores. Patients wi th two or more abnormal scores on static posturography were significantly m ore agoraphobic than those with less than two. Abnormal posturography score s under the eyes-opened was related to high anticipatory anxiety, whereas t hose under eyes-closed was related to phobic avoidance. Symptomatological r eactivity to CO2 was significantly correlated to abnormal functions of the balance system in the eyes-closed condition, Our findings suggest that (1) many patients with PD (5-42%) have abnormalities in their balance system fu nction compared with healthy controls (0-5%). (2) symptomatological reactiv ity to CO, and balance system function in patients with PD are correlated o nly in the eyes-closed condition and (3) there is a significant link betwee n agoraphobic avoidance and subclinical abnormal function of the balance sy stem network. (C) 2001 Elsevier Science Ltd. All ri-hts reserved.