Neuropsychiatric symptoms in mild cognitive impairment: a population-based study

Introduction: Few studies have examined neuropsychiatric symptoms in community dwelling older adults with mild cognitive impairment (MCI). In the present study, we compared the prevalence of neuropsychiatric symptoms in older adults with normal cognition, MCI, and dementia in a population-based sample. Methods: Subjects were selected from the Singapore Longitudinal Ageing study. Normal cognitive function was defined as Clinical Dementia Rating (CDR) global score = 0 and Mini-Mental State Examination (MMSE) total score >= 24. MCI was defined as CDR global score = 0.5, and dementia was defined as CDR global score >= 1. Neuropsychiatric Inventory (NPI) was administered on reliable informants for 293 subjects ( 136 normal, 133 MCI, and 24 dementia). Results: The prevalence of neuropsychiatric symptoms ( at lest one symptom) was 5.9% for normal cognition, 12.8% for MCI, and 50% for dementia. The most common neuropsychiatric symptoms in subjects with MCI were depression/dysphoria (6.8%), irritability/lability (3.8%), apathy/indifference (2.3%), and agitation/aggression ( 2.3%). NPI total score increased with increasing CDR global score (P < 0.001). The adjusted mean NPI total score was 0.07 (SEM = 0.49) for normal cognition, 0.86 ( SEM = 0.46) for MCI, and 4.50 ( SEM = 0.82) for dementia. Discussion: In community dwelling Asian older adults, we found an increasing prevalence of neuropsychiatric symptoms in subjects with normal cognition, MCI and dementia. Further studies with larger samples and strict criteria for MCI in an Asian population should be conducted.