The role of corticotropin-releasing factor in depression and anxiety disorders

Corticotropin-releasing factor (CRF), a 41 amino acid-containing peptide, a ppears to mediate not only the endocrine but also the autonomic and behavio ral responses to stress. Stress, in particular early-life stress such as ch ildhood abuse and neglect, has been associated with a higher prevalence rat e of affective and anxiety disorders in adulthood. In the present review, w e describe the evidence suggesting that CRF is hypersecreted from hypothala mic as well as from extrahypothalamic neurons in depression, resulting in h yperactivity of the hypothalamic-pituitary-adrenal (HPA) axis and elevation s of cerebrospinal fluid (CSF) concentrations of CRF. This increase in CRF: neuronal activity is also believed to mediate certain of the behavioral sy mptoms of depression involving sleep and appetite disturbances, reduced lib ido, and psychomotor changes. The hyperactivity of CRF neuronal systems app ears to be a state marker for depression because HPA axis hyperactivity nor malizes following successful antidepressant treatment. Similar biochemical and behavioral findings have been observed in adult rats and monkeys that h ave been subjected to early-life stress. In contrast, clinical studies have not revealed any consistent changes in CSF CRF concentrations in patients with anxiety disorders; however, preclinical findings strongly implicate a role for CRF in the pathophysiology of certain anxiety disorders, probably through its effects on central noradrenergic systems. The findings reviewed here support the hypothesis that CRF receptor antagonists may represent a novel class of antidepressants and/or anxiolytics.