Growth hormone response to clonidine in untreated depressed patients

Growth hormone (GH) responses to i.v. clonidine administration (150 micrograms) were compared in untreated depressed patients and controls. There were 8 controls (6 males, 2 females), 16 patients with a major depressive episode (8 males, 8 females), and 16 matched patients with a minor depressive episode according to Research Diagnostic Criteria. Differences in the GH response to clonidine only occurred between male patients and controls. These results suggest that endocrinological variables are important in the interpretation of this neuroendocrine test. Findings in the subgroup of unmedicated male patients with a nonendogenous major depressive episode support the hypothesis of decreased noradrenergic receptor sensitivity.