The prevalence and the course of neuropsychiatric symptoms in patients with dementia

Dementia is prevalent in Norway and other countries and is hallmarked by a decline in memory and other cognitive abilities. In addition to cognitive decline, the vast majority of patients with dementia experience neuropsychiatric symptoms (NPS) such as depression, agitation, psychosis, apathy, or irritability. In this review, we describe the prevalence and the course of NPS in patients with dementia, referring to results of population-based studies, studies of outpatients, and studies of patients in long-term care. For a better comparison of the included studies and for clarification, we have included studies that have assessed NPS with the Neuropsychiatric Inventory (NPI). Overall, we found a high prevalence rate of NPS. At least one NPS (NPI > 0) was present in 56% to 98% of the patients and 62% to 84% of the patients had at least one clinically significant NPS (NPI > 3). The NPS with the highest prevalence rate were apathy, irritability, agitation, depression and anxiety; while delusion, hallucination, disinhibition, aberrant motor behavior and euphoria were the least frequent NPS.