Agitation affects 70 to 90 percent of patients with AD. Signs of agitation include verbal and physical aggressiveness, irritability, wandering, and restlessness. These behaviors often make caring for patients at home very difficult. Trazodone and haldol are two of the most commonly prescribed drugs for agitation in AD patients. Behavior management, a non drug approach, has been effective in reducing signs of agitation. Researchers have yet to compare the effectiveness of drug versus non drug therapy to treat agitation in AD patients and determine which is the best treatment. The Alzheimer's Disease Cooperative Study, with funding from the National Institute on Aging, is conducting an agitation treatment program at 21 sites in 16 States. This study will assess which of the above treatments is most effective.