People suffering from depression generally have increased levels of the stress hormone cortisol. For decades, cortisol levels have been measured in blood, urine, and saliva, giving scientists information about levels at the time of collection. Now we can measure cortisol in segments of hair, which gives us a retrospective calendar of cortisol levels months ago. Because hair grows about 1cm per month, we can cut up bits of hair to get information of cortisol exposure in the last months. German researchers have been perfecting this new technology and wanted to see how far back they could detect cortisol profiles of depressed patients. Twenty-three medicated patients with depression were compared to 64 healthy adults. Using two 3-cm hair segments revealed that the depressive patients had higher levels up to 6 months ago. This fascinating finding opens doors of possibility to use cortisol in hair as a window to the past. This is important since different psychological conditions have distinct cortisol signatures: some are related to high levels (e.g., depression, anxiety) while others correspond to low levels (e.g., burnout, fatigue). Hair might give us the chance to further understand how this happens.
Title: Introducing a novel method to assess cumulative steroid concentrations: Increased hair cortisol concentrations over 6 months in medicated patients with depression
Authors: Lucia Dettenborn, Christophe Muhtz, Nadine Skoluda, Tobias Stalder, Susann Steudte, Kim Hinkelmann, Clemens Kirschbaum, & Christian Otte
Journal: Stress (2011), Early Online, 1-6