What role might hormones play in depression and anxiety?

Some studies have found that people with anxiety disorders have increased levels of excess corticotropin-releasing factor (CRF) in the cerebrospinal fluid, a clear liquid surrounding the brain and spinal cord. Research sponsored by the National Institute of Mental Health revealed that individuals with post-traumatic stress disorder have above-average levels of CRF. One study showed higher-than-normal levels of pituitary and adrenal stress hormones, such as cortisol and adrenocorticotropic hormone (ACTH), in the bloodstreams of women who had been physically or mentally abused as children. The levels were especially high in women who were experiencing symptoms of anxiety and depression at the time of the study.

This research suggests a biological explanation for why early stress or trauma increases the risk of developing an anxiety disorder in adulthood. Early trauma may cause a lasting increase in CRF and other stress hormones, and the pumped-up levels of these hormones may keep the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic system in a state of alert.