Neuropsychiatric Symptoms and Cognitive Impairment: Understanding the Importance of Co-Morbid Symptoms

Abstract

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.

Prevalence of Mild Behavioral Impairment and Risk of Dementia in a Psychiatric Outpatient Clinic

“…Neuropsychiatric symptoms (NPS) are common in the older population. A previous community based study reported that 38.9% of community-dwelling older adults had NPS [1], with the prevalence 506 T. Matsuoka et al / MBI in a Psychiatric Outpatient Clinic increasing as cognitive function declined. The rates ranged from 30.8% in the cognitively normal population to 80% in those with dementia [1].…”

“…While the annual progression rate of dementia in patients with mild cognitive impairment (MCI) is approximately 12% [9], the progression rate in MCI patients with NPS is estimated at 25% [10]. Those with NPS have a 3-fold greater risk of dementia than those without NPS [1]. NPS, especially psychosis, agitation, and aggression, were detected as predictors of progression to severe dementia and death [11].…”

Neuropsychiatric symptoms as a distinguishing factor between memory diagnoses

“…They did not find as clear results for if NPS influence risk of dementia. In a cross-sectional study by Mortby, Burns, Eramudugolla, Ismail, & Anstey, 6 and a longitudinal study by Acosta, Borges, Aguirre-Hernandez, Sosa, & Prince, 7 the presence of NPS at baseline were able to significantly predict an MCI or dementia diagnosis. Specifically, the presence of one NPS increased the likelihood of MCI by 2-fold and dementia by 3-fold.…”

“…Further, having more than one NPS elevated the likelihood of dementia. 6 If NPS are associated with future cognitive declines, then they should be differentially represented among persons with different cognitive impairment syndromes. Evidence for this pattern has been observed where those with dementia have been found to have more NPS than those with or without MCI 6 and those with MCI have been found to have more NPS than those without cognitive impairment.…”

“…6 If NPS are associated with future cognitive declines, then they should be differentially represented among persons with different cognitive impairment syndromes. Evidence for this pattern has been observed where those with dementia have been found to have more NPS than those with or without MCI 6 and those with MCI have been found to have more NPS than those without cognitive impairment. 8 When considering individual symptoms, Brodaty et al 9 found that anxiety had the strongest cross-sectional relationship with cognitive impairment, and depression was related to the diagnosis of dementia.…”