Dexamethasone suppression test in early- and late-stage patients with bipolar disorder type I and first-degree relatives: a preliminary analysis

Evidence suggests that Bipolar Disorder (BD) type I present a progressive feature, in which patients become less responsive to medications and less resilient to stress over time. Therefore, this study aimed to assess the hypothalamus-pituitary-adrenal (HPA) axis in patients with BD at early and late stages of disease and in first-degree relatives. Thirteen euthymic patients with BD type I were recruited and divided into early-stage (n = 6) and late-stage (n = 7) groups. Moreover, 9 age- and sex-matched first-degree relatives and 12 healthy controls were also recruited. Participants performed a dexamethasone suppression test (1 mg), collecting saliva at 8 pm two days in a row, before and after the administration of dexamethasone at 11 pm. All groups significantly suppressed cortisol levels, even though basal cortisol levels did not differ between groups. However, postdexamethasone cortisol levels were significantly increased in late-stage patients when compared to controls. No further differences were found in relatives or early-stage patients. In addition, postdexamethasone cortisol significantly correlated with mood symptoms scores. No significant correlations were found between cortisol and number of mood episodes, hospitalizations and suicide attempts. Our results suggest that patients with BD at a late stage of illness present an impaired negative feedback of the HPA axis, which may be related to clinical parameters reported in patients along with illness progression. This study was supported by INCT for Translational Medicine, CNPq, Brazil