Neuropsychiatric symptoms in dementia represent a major health burden for older adults. These symptoms are often more distressing, impairing, and costly than cognitive symptoms in dementia, yet they have been less coherently categorized in the various versions of the Diagnostic and Statistical Manual of Mental Disorders (DSM). The preponderance of literature on psychiatric symptoms in dementia has been in patients with Alzheimer's disease. Diagnostic criteria have been proposed for psychosis, depression, and sleep disturbance in Alzheimer's disease. "Agitation" also appears to be a clinically important behavioral complication of dementia that warrants further study. Beginning with further validation of these proposed diagnostic criteria, future research can guide a more clinically meaningful description of these syndromes in DSM-V. Advancing biotechnology offers promise for discoveries related to the etiology and treatment of these syndromes. New research in this field should encompass diverse populations and different types of dementia. The high emotional and economic costs of neuropsychiatric symptoms in dementia implore diagnostic refinement to facilitate improved treatment.