The Neuropsychiatric Inventory (NPI) was introduced in 1994 and has since become a standard instrument for clinical trials and other types of behavioral research in dementing disorders. Its reliability and validity have been confirmed. The NPI was the subject of a workshop in Asia in conjunction with the International Workgroup on Dementia Drug Guidelines (IWG). Investigators using the NPI from 4 Asian areas--Taiwan, Hong Kong, Japan, Thailand--presented conclusions from their research. A high prevalence of behavioral disturbances across Asian countries was found and the rates are similar to those observed in Western countries. Apathy is more difficult to detect and characterize in Asian populations. Neurobiologic studies show an excess of some serotonin receptor gene polymorphisms in patients without behavioral disturbances and positron emission tomography reveals reductions in frontal lobe metabolism in patients manifesting depression as measured by the NPI. Studies in Thailand show relationships among verbal fluency, activities of daily living, and neuropsychiatric symptoms particularly agitation, apathy, and disinhibition. This suggests a triad of symptoms of behavioral abnormalities, executive dysfunction, and abnormalities of activities of daily living that impugn frontal lobe function. The NPI is a reliable and useful instrument to characterize behavioral changes in Asian and Western populations.