Neuroendocrine stimulatory tests of hypothalamus-pituitary-adrenal axis in psoriasis and correlative implications with psychopathological and immune parameters

Abstract

Psoriasis constitutes one of the most representative examples of psychosomatic disorders. The published work investigating the psychological parameters and the way they interact during the course of the disease is extensive, whereas only a few studies have focused on the neuroendocrine framework of psoriasis. In the present study, the objective was to investigate the neuroendocrine parameters of psoriasis and the way they interact with psychopathological and immune variables. Patients with psoriasis (n=24) and the same number of matched healthy controls underwent psychiatric evaluation with interviews and psychometric questionnaires. Both of the groups underwent the corticotropin-releasing hormone (CRH) test and the dexamethasone suppression test (DST) to investigate functional parameters of the hypothalamus-pituitary-adrenal (HPA) axis. The evaluation of immune variables included the estimation of the distribution of T-cell and natural killer lymphocytes. Levels of depressive and anxiety features were increased within subjects with psoriasis and they were significantly correlated with stressful life events and the extent of the disease. The adrenocorticotrophic hormone and cortisol levels increased after CRH infusion without significant differences between the two groups and the psoriatic subjects' cortisol suppression after DST was within normal range, though relatively blunted. No significant correlations were identified among neuroendocrine, psychopathological and immune parameters. No particular neuroendocrine profile has been identified among psoriatic patients and the hypothesized interaction with psychopathological and immune parameters was not replicated. Nevertheless, it is still premature to exclude the possibility that a subtle latent alteration of the HPA axis function might exist, in psoriasis, either stemming from the psychopathology or from the disease per se.