Growth hormone releasing hormone improves the cognition of healthy older adults

Declines in the activity of the somatotrophic axis have been implicated in the age-related changes observed in a number of physiological functions, including cognition. Such age-related changes may be arrested or partially reversed by hormonal supplementation. We examined the effect of 6 months treatment with daily growth hormone releasing hormone (GHRH) or placebo on the cognition of a group of 89 healthy older (68.0 ± 0.7) adults. GHRH resulted in improved performance on WAIS-R performance IQ (p < 0.01), WAIS-R picture arrangement (p < 0.01), finding A's (p < 0.01), verbal sets (p < 0.01) and single–dual task (p < 0.04). GHRH-based improvements were independent of gender, estrogen status or baseline cognitive capacity. These results demonstrate that the age-related decline in the somatotrophic axis may be related to age-related decline in cognition. Further they indicate that supplementation of this neuro-hormonal axis may partially ameliorate such cognitive declines in healthy normal older adults and potentially in individuals with impaired cognitive function (i.e., mild cognitive impairment and Alzheimer's disease).