Cognitive changes during growth hormone replacement in adult men

Area of Science:

• Endocrinology
• Neuroscience
• Psychology

Background:

• Adults with childhood-onset growth hormone deficiency (CO-GHD) often experience persistent cognitive deficits.
• Growth hormone (GH) replacement therapy is a standard treatment for GH deficiency, but its long-term effects on cognition in adults are not fully understood.

Purpose of the Study:

• To evaluate the impact of 2-year GH replacement therapy on psychological well-being and cognitive performance in adult men with CO-GHD.
• To compare the effects of physiological versus supraphysiological GH dosing on memory and psychological outcomes.

Main Methods:

• A randomized, placebo-controlled trial involving 48 adult men with CO-GHD.
• Participants received placebo or GH doses of 1, 2, or 3 IU/m2 for up to 2 years.
• Cognitive and psychological assessments, including memory tests and well-being questionnaires, were conducted every 6 months.

Main Results:

• GH replacement therapy positively correlated with improvements in memory performance, linked to insulin-like growth factor-I (IGF-I) levels.
• Memory function improved in patients receiving supraphysiological GH doses within 6 months, and in those with normalized IGF-I after 1 year.
• No significant changes were observed in psychological well-being or perceptual-motor skills throughout the study.

Conclusions:

• GH replacement therapy effectively improves memory function in adults with CO-GHD.
• Supraphysiological GH dosing accelerates memory recovery, but long-term benefits are comparable to physiological replacement.
• GH therapy does not appear to influence psychological well-being or perceptual-motor skills in this population.