The Alzheimer's Disease Cooperative Study (ADCS) started in 1991 as part of an agreement between the National Institute on Aging (NIA) and the University of California, San Diego, is a major clinical activity for treating Alzheimer's disease (AD). As part of the NIA Division, the ADCS supports all activities for AD treatment, including the discovery and evaluation of new diagnostic methods, drugs, and devices for patients with AD, as well as the prevention of AD.