In clinical practice, the behavioral disturbances seen in patients with dementia are helpful in determining disease severity and the need for support care. In patients with Alzheimer's disease, the early appearance of behavioral symptoms is associated with faster disease progression. Until recently, pharmaceutical companies have had little interest in developing drugs to treat behavioral disturbances, because the U.S. Food and Drug Administration, in the “Guidelines for the Clinical Evaluation of Antidementia Drugs” dated November 8, 1990, held that drugs acting on noncognitive symptoms associated with Alzheimer's disease would be “pseudospecific” (i.e., not targeted to the core cognitive domains of Alzheimer's disease). As a result, few measurement scales were specifically developed to assess functional autonomy and behavior in patients with Alzheimer's disease within time frames of 3 to 6 months, the typical length of double-blind, placebo-controlled studies. Many of the existing scales included heterogeneous items relevant to cognition, functional autonomy, somatic symptoms, and psychiatric problems. The Dementia Behavior Disturbance (DBD) scale was developed in the late 1980s, a time when the importance of behavioral symptoms in dementia was increasingly being recognized. Recent harmonization efforts for the development of antidementia drugs have further emphasized the clinical importance of noncognitive symptoms in dementia.