This review focuses on the role of corticotrophin-releasing hormone (CRH) in the pathogenesis of Alzheimer's disease (AD) and briefly discusses its role in other dementias, including Parkinson's disease (PD), progressive supranuclear palsy (PSP) and Huntington's disease (HD). During aging the hypothalamic-pituitary-adrenal (HPA) axis changes, which has repercussions on hormonal levels in the brain. The significance of these changes has been examined by many researchers, but the relationship between CRH and other neurotransmitters needs to be further explored.