The conceptualization and research focus on the behavioral and psychological manifestations of dementia have increased significantly over the past decade. To reflect this evolution, a recent consensus conference, convened by the International Psychogeriatric Association and subsequent to the compilation of this issue, concluded that the term “behavioral disturbances of dementia” (BDD) be replaced by “the behavioral and psychological signs and symptoms of dementia” (BPSSD).

Behavioral disturbances of dementia have been noted by early researchers in the field, including Esquirol (1838) and Alzheimer in his seminal case description (1907). Increasingly, family members, healthcare providers, and policy makers are realizing that neuropsychiatric symptoms and behavioral problems are an intrinsic component of Alzheimer's disease and result in caregiver psychopathology, early institutionalization, substantial societal costs, and detriment in the quality of life for the patient and caregivers.

With a world population increasing in size and age, the number of elderly people with behavioral distrubances in dementia (BDD) is becoming an increasing problem. The burden of caring for someone with BDD may be so great that it leads to premature institutionalization of the patient. Few clinical trials have focused on noncognitive behavioral symptoms in this group of elderly patients, and little is known about the efficacy of drugs against these symptoms. The pharmaceutical companies have recently begun to assess different medications, but clinical trials in the elderly present a variety of problems not encountered in other patient populations. This article describes how the administration, initiation, logistics, finances, and methodology of such trials must be carefully assessed. Consideration of these factors together with improved definitions of behavioral symptoms and the advances in medication in this area should lead to an improvement in the treatment and management of behavioral disorders in the elderly.

Before evaluating behavioral distrubances of dementia (BDD), several factors should be considered. This includes the patient population, the properties of the rating scales to be used, and the assessor. The frequency of behavioral symptoms appears to vary between countries, making comparisons in multinational studies difficult. These variations may be caused by cultural differences, clinicians' attitudes to behavioral symptoms, and interrater variability. The psychometric properties of a rating scale may be affected by differences in clinicians' attitudes in different countries, which may, in turn, alter the frequency of diagnosis of BDD, causing problems in the interpretation of data in multinational studies. Consideration should be given to all these factors before initiating a multinational clinical trial.

Behavioral disturbances in dementia are some of the most burdensome features with which the caregivers must cope. These symptoms are particularly important because they are likely to be responsive to both pharmacological and nonpharmacological intervention strategies. Before the 1980s, rating scales for patients suffering from dementia did not separate cognitive features from noncognitive behavioral symptoms. This was a major problem because the evolution and course of behavioral symptoms in dementias, such as Alzheimer's disease, is different from the evolution and course of cognitive and cognition-related symptomatology. Before appropriate rating scales could be developed for the assessment of behavioral disturbances in dementia, the specific nature of these disturbances had to be described in the medical literature. Publications in the late 1980s described the specific behavioral diturbances occurring in dementia patients in detail for the first time. The rating scales that have been developed from these studies are as reliable as cognitive assessment measures. Instruments are now available that are based on information provided by the caregiver or that are based on observation of the patient made by the clinician. Construct validity, reliability, and the differences in methodology of these scales are compared in this overview. Using these scales will enable clinicians to assess pharmacological and nonpharmacological intervention strategies for behavioral symptoms in dementia with enhanced sensitivity.

Behavioral disturbances are a prevalent and important aspect of dementia of the Alzheimer type, but they have been relatively neglected by researchers. To characterize patients as having dementia, at least two goals should be addressed: first, determining a reliable definition and categorical diagnosis of dementia using such criteria as the Diagnostic and Statistical Manual of Mental Disorders (DSM)–IV and the International Classification of Diseases (ICD)–10; second, establishing a reliable and valid measurement of the severity of cognitive and noncognitive impairment by means of rating scales. DSM-IV and ICD-10 do not provide definitions of behavioral disturbance, whereas more than 100 geriatric rating scales exist that include some measurement of behavioral disturbances of dementia. There is a need for consensus on the term for these noncognitive symptoms. Some authors prefer the subdivisions of (a) psychiatric and noncognitive symptomatology into psychiatric symptoms, or syndromes and behavioral distrubances; and (b) cognitive syndromes. Given the frequency and clinical significance of behavioral and psychiatric disturbances in dementia, a standardized assessment procedure is needed for reliably and comprehensively describing psychiatric phenomena and behavioral disturbances in patients with dementia.

Psychiatric symptoms and behavioral disturbances in dementia (sometimes referred to as noncognitive features of dementia or neuropsychiatric symptoms) are important aspects of the clinical syndrome of dementia. Despite their significance, there have been few studies concentrating on these features from the viewpoint of therapy. This article reviews some of the studies that have been carried out. For more detailed reviews, the reader is referred to Schneider and Sobin (1994) and Burns (1994).