Affiliations: [a] Centre for Research on Ageing, Health andWellbeing, Research School of Population Health, The Australian National University, Canberra, Australia
| [b]
NHMRC National Institute for Dementia Research, Australia
| [c] Departments of Psychiatry and Clinical Neurosciences, Mathison Centre for Mental Health Research &Education, Ron and Rene Centre for Healthy Brain Aging Research, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
Correspondence:
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Correspondence to: Moyra E. Mortby, PhD, Centre for Research on Ageing, Health and Wellbeing, Florey Building, 54 Mills Road, The Australian National University, Canberra, ACT 2601, Australia. Tel.: +61 253858; Fax: +61 258413; E-mail: moyra.mortby@anu.edu.au.
Abstract: Background: Neuropsychiatric symptoms (NPS) are common in older adults with cognitive impairment, yet little is known about population-based prevalence and clinical implications of co-morbid symptom presentation across the spectrum from normal cognition to dementia. Objective: To characterize the prevalence of NPS and explore the clinical implications of co-morbid symptom presentation. Methods: Cross-sectional study of 1,417 older adults (aged 73–79) with dementia (n = 40); with mild cognitive impairment (MCI; n = 133); who are ‘cognitively normal, but-at-risk’ (CN-AR; n = 397); and who are cognitively normal (n = 847). NPS were assessed by the Neuropsychiatric Inventory. Cluster analyses were conducted using a latent class analysis (LCA). Results: NPS are highly prevalent across the cognitive function spectrum (30.8% –80%). NPS were associated with a 3-fold increased risk of dementia, a 2-fold increased risk of MCI, and a 1.5-times increased risk of CN-AR. Each additional co-morbid symptom was associated with an additional 1.5-times increased risk of dementia, but not MCI or CN-AR. LCA revealed four distinctive sub-populations: 1) frontal/low comorbidity; 2) high prevalence/high comorbidity; 3) affective/low comorbidity; and 4) sleep/low comorbidity. Conclusion: Our findings confirm previous reports on the prevalence of NPS in community-based samples and are consistent with the profiles of NPS domain characteristics of MCI and dementia. Number of co-morbid NPS and not symptom clusters are associated with increased risk of dementia. Understanding such patterns will help inform our understanding of mild behavioral disorders and assist with clinical assessment.
