Noncognitive behavioral and psychiatric disturbances are common in dementia and help in the clinical differentiation of the various subtypes. We studied the frequency of neuropsychiatric disturbances, their relationship to dementia severity and compared these disturbances in Alzheimer's disease (AD), vascular dementia (VaD) and frontotemporal dementia (FTD) using the 12-item Neuropsychiatric Inventory (NPI). A total of 98 patients (AD-44, VaD-31, FTD-23) were evaluated. All subjects were community dwelling at the time of evaluation. The three groups were comparable on global dementia severity and functional ability. All patients had clinically significant scores on the NPI with apathy, irritability and agitation being very common (>90% of patients). AD and VaD patients in Clinical Dementia Rating (CDR) stage 2 had significantly higher scores on the total NPI, agitation and disinhibition subscales compared to those in CDR stage 1. Mean scores in the domains of aberrant motor behavior, disinhibition and appetite/eating behavior differentiated FTD from AD and VaD. Neuropsychiatric disturbances in dementia appear to be universal with agitation, disinhibition and irritability being more frequent in the later stages. In this cohort disinhibition, aberrant motor behavior and appetite/eating disturbances could reliably differentiate AD and VaD from FTD. There were no significant differences between the neuropsychiatric profiles of AD and VaD.