Abstract Introduction Elevated levels of the hypothalamic-pituitary-adrenal axis hormone cortisol are a frequently replicated finding in major depressive disorder (MDD). However, the current state of research is inconclusive as to whether hypercortisolism represents a trait- or state-like biological signal of MDD. The aim of the present study was to investigate, for the first time, whether cortisol in fingernails, a highly accessible tissue, could distinguish currently remitted individuals with MDD from healthy controls. A further aim was to identify potential confounders of nail cortisol. Methods A total of N = 100 individuals from the general population were recruited. A structured clinical interview was administered, which resulted in two groups: n = 48 with lifetime MDD and n = 52 healthy controls. All participants answered questions on sociodemographic, lifestyle, and psychosocial characteristics. They also grew their nails for 14 days and cut them for the subsequent determination of cortisol. Results The groups differed in their nail cortisol concentrations, such that the individuals with lifetime MDD had significantly higher concentrations than the healthy controls ( p = 0.041). Within the group of individuals with lifetime MDD, the number of experienced episodes was significantly correlated with cortisol ( p = 0.011). Income emerged as the only significant confounder of cortisol ( p = 0.008). Conclusion Elevated fingernail cortisol appears to be a biological signal of MDD, even in the absence of a current major depressive episode. Its high accessibility and robustness render it a promising methodology for remote research as well as for the integration of biomarkers into clinical research and practice.
【저자키워드】 Biomarkers, Depression, Stress, cortisol, hypothalamic-pituitary-adrenal axis,