Commentary: Is there a there there in hair? A reflection on child maltreatment and hair cortisol concentrations in White et al. (2017).

Both chronic and acute stressors have typically been understood to produce elevations in cortisol, as a means to maintaining homeostatic balance. In the past two decades, however, individuals experiencing high levels of chronic early adversity have been shown to manifest an alternate profile involving blunted cortisol levels. In the context of this emerging evidence, a number of questions about diminished cortisol have remained unclear. The study by White et al. (2017) is the first to measure hair cortisol concentrations in the context of adversity, and provides validation for the stability of diminished cortisol in maltreated individuals, the association between neglect and low cortisol, and a mediating role for dysregulated hypothalamic-pituitary-adrenal axis activity in the association between early maltreatment and behavioral dysregulation.