The sleep of Alzheimer's disease (AD) patients is often disturbed by medications, depression, circadian rhythm changes and sleep disorders. Institutionalization is often precipitated by the effect of the patient's sleep and wakefulness on the caregiver. We examined reports of sleep disturbance in mild AD patients. The study cohort consisted of 246 AD patients and 94 controls. Self-reports of sleep disturbance in mild AD patients were examined as was the relationship of sleep and medication use. Results were compared to those of normal controls, and the patients' responses to the reports of their caregivers. Dementia was assessed with the Mini Mental Status Exam, the Blessed Dementia Scale, the Mattis Dementia Rating Scale, and the Pfeiffer Outpatient Disability Test. The more demented the patients, the more time they spent in bed, the more fragmented their sleep, and the more naps they took. Caregivers reports of increased wandering at night and more aggressive behavior during the day were associated with increased use of sedative-hypnotics and with going to bed early. Lengthy sleep was associated with disruptive behavior. We conclude that increased sleep may be associated with dementia and with more disruptive behavior.