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 with fluoxetine on human growth hormone (GH) response to the alpha 2 agonist clonidine.

METHOD

Seventeen patients with panic disorder and 15 healthy volunteers were challenged with clonidine. Thirteen of the patients and 12 of the volunteers were given a second challenge with clonidine 12 weeks later. The patients received open fluoxetine and the healthy subjects received no treatment between challenges. Subjects with high baseline human GH levels (greater than 2 ng/ml) at the first and second challenges were excluded from further analysis.

RESULTS

The patients with panic disorder (N = 13 for the first challenge and N = 9 for the second) had significantly lower human GH responses to clonidine than the healthy subjects (N = 14 during the first challenge and N = 9 for the second) during both challenges, despite clinical improvement in eight of the nine patients at the time of the second challenge.

CONCLUSIONS

Blunted secretion of human GH in response to clonidine in patients with panic disorder persists despite clinical recovery.