Background: Determination of the prevalence of neuropsychiatric symptoms in elderly patients with dementia in Mungialde. Methods: 108 subjects with dementia, who participated in a door-to-door epidemiological study, were included. The 12-item Spanish version of the Neuropsychiatric Inventory was used to evaluate these symptoms. Results: The prevalence of at least 1 neuropsychiatric symptom was found to be 76.90% for all dementia types, 73.50% in patients with Alzheimer's disease (AD), 80% for the Parkinson-Lewy body dementia complex (PLBD), 78.60% for vascular dementia (VD) and 100% for frontotemporal dementia (FTD). Apathy was found to be the most prevalent symptom for all dementia types and in patients with AD (53.70 and 54.30%, respectively). The next most prevalent symptoms were anxiety, depression and sleep disturbances (35.20, 32.40 and 30.60%) for all dementia types, and anxiety and depression (32.10 and 30.90%) in patients with AD. The most prevalent symptoms in patients with PLBD were apathy, appetite changes, sleep disturbances and agitation (50% each); in patients with VD they were apathy, depression and anxiety (42.90% each), and in patients with FTD they were apathy, anxiety and aberrant motor activity (100% each). Conclusions: Neuropsychiatric symptoms were found to be prevalent in patients with dementia, irrespective of dementia type. Copyright (C) 2007 S. Karger AG, Basel.