Low growth hormone response to growth hormone-releasing hormone in child depression

Background: This study examined growth hormone (GH) response to growth horm one-releasing hen-none (GHRH) in a large sample of depressed children compa red with normal control children, Within-subject comparisons were also perf ormed in control subjects to examine test-retest reliability and in depress ed children comparing episode versus clinical recovery. Methods: The sample included depressed children (n = 82) and normal control children (n = 55) group-matched for age, gender, and pubertal status; the mean ages were 11.2 +/- 1.7 and 11.2 +/- 1.8 years, respectively. We gave G HRH (0.1 mcg/Kg) at 9 AM, and serum GH levels were determined every 15 min from -30 min through +90 min of the GHRH infusion. A subgroup of normal con trol subjects (n = II) repeated the protocol for test-retest reliability wi thin a 2-month interval. A subgroup of depressed children (n = 20) were res tudied of all medications following full clinical remission from depression . Results: The mean GH response to GHRH was significantly lower in the depres sed group (8.7 ng/mL +/- SEM 0.9) compared with normal control children [12 .2 ng/ mL +/- SEM 1.3; t(135) = 2.59, p = .01 effect size 0.44], The test-r etest reliability of GH response to GHRH was stable (intraclass correlation = .93 for mean post-GH), The GH response to GHRH remained low in subjects restudied during clinical remission from depression. Conclusions: Depressed children show low GH response to GHRH, The measure a ppears to be reliable, and the low GH response continues following clinical remission. Further studies are needed to explore the mechanism and relativ e specificity of this finding. (C) 2000 Society of Biological psychiatry.