Longitudinal growth hormone studies in schizophrenia.

Area of Science:

• Neuroendocrinology
• Psychiatry

Background:

• Growth hormone (GH) secretion is regulated by various factors, and its dysregulation may be implicated in schizophrenia.
• Apomorphine hydrochloride (APO) is a dopamine agonist used to test GH release.

Purpose of the Study:

• To investigate the longitudinal growth hormone (GH) response to apomorphine hydrochloride (APO) in patients with schizophrenia compared to healthy controls.
• To explore the relationship between GH response, symptom severity, relapse, and body weight changes in schizophrenia.

Main Methods:

• Monthly apomorphine hydrochloride (APO) challenges were administered to 12 schizophrenic patients on drug holiday and age/sex-matched controls for up to 22 months.
• Longitudinal GH response data were analyzed, with a subgroup studied for 12 consecutive trials.
• Correlations between GH response, positive symptom scores, relapse, and body weight changes were assessed.

Main Results:

• Schizophrenia patients exhibited greater variability in GH response to APO compared to controls, especially on initial trials.
• Longitudinal analysis revealed significantly lower average GH response to APO in patients versus controls over 12 trials.
• GH responsiveness in patients decreased over successive trials, becoming significantly different from controls in later trials, though some showed increased responsivity after 12 trials.
• A trend suggested an association between relapse and GH increment, and a significant link was found between body weight changes and GH response variability.

Conclusions:

• Longitudinal assessment reveals a blunted and progressively decreasing GH response to APO in schizophrenia patients compared to controls.
• Variability in GH response to APO in schizophrenia may be influenced by factors such as body weight fluctuations.
• The findings suggest potential neuroendocrine alterations in schizophrenia that may relate to disease progression and treatment response.