Investigating the stability of neuropsychiatric sub-syndromes with progression of dementia: a 2-year prospective study

Objectives Previous studies have identified sub-syndromes of behavioral and psychological symptoms of dementia. But because of their cross-sectional design, the stability of these sub-syndromes over time remains unknown. Method Behavioral and psychological symptoms of dementia of 84 participants (out of an original sample of 144 patients) with Alzheimer's disease and vascular dementia were assessed by using the Neuropsychiatric Inventory every six months for two years. Principal component factor analysis with Varimax rotation was used to detect neuropsychiatric sub-syndromes at each time point. Results The 12 symptoms were reduced to four factors at baseline, 12, 18, and 24?months and three factors at six months. None of the factor structures matched the four sub-syndromes previously identified by studies. The most stable group of symptoms were a combination of psychosis and hyperactivity symptoms (delusions, hallucinations, irritability, agitation), which became stable at 18?months. Conclusions The pattern of behavioral and psychological symptoms of dementia sub-syndromes over time has not been studied before, and this research suggests that some stability is evident particularly during the later stages of the disease process. These findings have implications for patients and their caregiver. Copyright (C) 2012 John Wiley & Sons, Ltd.