Cognitive changes during growth hormone replacement in adult men.
The present study evaluates the effects of 2 years of growth hormone (GH) replacement therapy on psychological well-being and cognitive performance in adults with childhood-onset growth hormone deficiency (CO-GHD). A total of 48 GHD adult men (mean age: 27 years) were randomly assigned to one of four treatment groups: placebo treatment, or GH replacement in a dose of 1, 2, or 3 IU/m2, respectively. Placebo treatment was given for 6 months. Psychological assessments were made every 6 months. Assessments included somatic and psychological complaints, depression, fatigue, vigor, tension, state/trait anxiety, iconic memory, short-term memory, long-term memory and perceptual-motor skill. GH treatment was considered physiological if the observed insulin-like growth factor-I (IGF-I) levels were within the normal range. It was considered supraphysiological if serum IGF-I rose to a value exceeding the upper normal limit. During the placebo-controlled phase of the study the changes in memory performance were positively correlated to the GH induced changes in serum IGF-I concentration and, more weakly, to the daily GH substitution dose. At 6 months memory only had improved in the group receiving supraphysiological GH treatment, but not in the group of patients who had a normalization of serum IGF-I. However, after 1 year of treatment a normalization of memory functioning was found in both groups of patients and this was preserved during the 2nd year of treatment. No changes were observed in psychological well-being and perceptual-motor skill. We conclude that GH replacement improves memory function in adults with CO-GHD. It has no effect on psychological well-being or perceptual-motor skill. Supraphysiological treatment accelerates the recovery of memory performance. However, the long-term effects are not different from those achieved with physiological GH replacement.
Deijen
J B
JB
Department of Psychophysiology, Free University, Amsterdam, The Netherlands. jb.deijen@psy.vu.nl
de Boer
H
H
van der Veen
E A
EA
D000328:Adult; D000339:Affect / Q000187:drug effects; D003071:Cognition / Q000187:drug effects*; D013006:Growth Hormone / Q000172:deficiency* / Q000627:therapeutic use*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008568:Memory / Q000187:drug effects; D010907:Pituitary Hormones / Q000172:deficiency*; D011581:Psychological Tests; D011597:Psychomotor Performance / Q000187:drug effects
D010907:Pituitary Hormones; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone