Cortisol awakening response and cortisol/DHEA ratio associations with hippocampal volume in MDD

Prior studies of Hypothalamic-Pituatary-Adrenal (HPA) associations with hippocampal (HC) volume have yielded inconsistent results. This might be due to the use of basal cortisol rather than cortisol reactivity measures and to the use of cortisol in isolation from related steroids. Therefore, in this study, we assessed the relationship of HC volume to cortisol awakening responses (CARs) and to the ratio of cortisol/DHEA in depressed (MDD) subjects and healthy controls. We additionally assessed cortisol correlations with individual HC subfield volumes.A 4 Tesla T1 MR imaging was conducted for HC volume for 19 MDD subjects and 19 matched controls. Fasting morning serum was assayed for cortisol and DHEA. In addition, salivary samples were assayed for cortisol for 17 MDDs and 15 controls across 3 days: at Waking (Sample 1) and at +30 minutes after waking (Sample 2). The CAR is the difference between daily Sample 1 and Sample 2 salivary concentrations. The slope of the CARincrease was obtained by dividing the CAR by the actual length of time between the two sample collections. Serum cortisol was not significantly correlated with HC volume. However, in the MDD group, serum DHEA, a putative anti-glucocorticoid, was positively correlated with HC volume (p