PERSISTENCE OF BLUNTED HUMAN GROWTH-HORMONE RESPONSE TO CLONIDINE IN FLUOXETINE-TREATED PATIENTS WITH PANIC DISORDER

Objective: The authors determined the effects of antipanic treatment w ith fluoxetine on human growth hormone (GH) response to the at agonist clonidine. Method: Seventeen patients with panic disorder and 15 heal thy volunteers were challenged with clonidine. Thirteen of the Patient s and 12 of the volunteers were given a second challenge with clonidin e 12 weeks later. The patients received open fluoxetine and the health y subjects received no treatment between challenges. Subjects with hig h baseline human GH levels (greater than 2 ng/ml) at the first and sec ond challenges were excluded from further analysis. Results: The patie nts with panic disorder (N=13 for the first challenge and N=9 for the second) had significantly lower human GH responses to clonidine than t he healthy subjects (N=14 during the first challenge and N=9 for the s econd) during both challenges, despite clinical improvement in eight o f the nine patients at the time of the second challenge. Conclusions: Blunted secretion of human GH fit response to clonidine in patients wi th panic disorder persists despite clinical recovery.