This article proposes new standards for identifying, defining, and naming sleep/wake cycle disturbances associated with Alzheimer's disease (AD) to aid in more effective research, including the development and testing of potential treatments. Many AD patients develop sleep/wake cycle disturbances associated with distress, depression, and sleep disturbances in the caregiver, as well as early nursing home placement for the patient. The Food and Drug Administration Psychopharmacological Drugs Advisory Committee has emphasized the need for a comprehensive diagnostic system. A key point made by the committee was that behavioral problems associated with dementia (including sleep and chronobiological disturbances) are scientifically and clinically valid targets of pharmacologic treatment. However, current diagnostic criteria preclude development of FDA-acceptable studies of pharmacological interventions because they do not include the required specific indications for treatment. This article attempts to develop better-defined provisional criteria with the goal of promoting epidemiological, physiological, and, especially, pharmacological research on sleep/wake disturbances.