[Causal analytic studies on demonstration of neuroendocrine parameters in combined hypoglycemia test in depressive...

With the help of an analytical path structure model (causal analysis) the aim of the study was to elucidate further, in female patients with various depressive disorders, some correlations of causal interdependencies between changes both in basal secretion of anterior pituitary hormones and in their responses to the (combined) insulin tolerance test (ITT) with extraneous factors--such as age, deviation from ideal body weight (in percentage), severity of depression and score in the Newcastle Scale (NCS)--that may influence these abnormalities. In various depressive subgroups the strength of influence and the different importance of deviation from ideal body weight and basal growth hormone (GH) concentration (as exclusion criteria) for their neuroendocrine reactivity in the combined ITT was shown. The hypothesis that cortisol hypersecretion may be the primary disturbance and the other possible neuroendocrine changes such as blunted GH, cortisol and TSH responses to stimuli in some depressive patients all may be secondary to the (elevated) cortisol level could not be corroborated. The endogenous mono- and bipolar subtypes of major depressive disorders showed intimate connections between the various neuroendocrine functional systems and the above mentioned extraneous factors resulting in a narrowed variability and a stronger coupling in the reactivity of these hormonal functional systems, a condition which can be seen as analogous to experimental results at the psychophysiological level in these nuclear groups of depressed patients, whose psychopathological state is also characterized by similar limitations in their "degree of freedom" (Heimann).