Higher cortisol levels may proceed a manic episode and are related to disease severity in patients with bipolar disorder

Abstract

BackgroundRegulation of the hypothalamic-pituitary-adrenal (HPA) axis is implicated in the pathogenesis of bipolar disorder (BD). However, the relationship between HPA-activity and disease severity is not fully elucidated. In this pilot study we aimed to explore the temporal relationship between HPA-activity and the risk of a manic episode in BD patients type I, by assessing long-term hair cortisol concentrations (HCC). Second, we explored the relation between HCC and the number of previous episodes. MethodsHair samples were collected from 45 BD I patients in euthymic or manic state and compared to 17 controls. From each participant, two hair samples of 3 cm length were used to measure long-term cortisol, reflecting retrospect time frames of 1–3 months and 4–6 months respectively prior to sampling. ResultsHCC in the BD group was slightly higher than in the control group in both hair segments (p = 0.049 and 0.03; after adjustment for age, sex, BMI and hair washing frequency p = 0.222 and 0.139). A significant peak in hair cortisol was observed prior to a manic episode (p = 0.036). Furthermore, we found a positive correlation between the number of mood episodes HCC (p = 0.03). ConclusionsOur results indicate that long-term cortisol levels are slightly higher in BD, and in particular elevated in the months prior to a manic relapse. In addition HCC are positively associated with the number of previous mood episodes in the course of BD type I.