Personality changes in Alzheimer's disease: a systematic review

Abstract

People with Alzheimer's disease (AD) commonly exhibit changes in personality that sometimes precede the other early clinical manifestations of the condition, such as cognitive impairment and mood changes. Although these personality changes reflect the impact of progressive brain damage, there are several possible patterns of personality change with dementia. Early identification of personality change might assist with the timely diagnosis of AD. The objective of this study was to review studies of personality change in AD. Systematic searches of the PubMed, Ovid Medline, EBSCOhost, PsychINFO and CINAHL databases were undertaken from inception to November 2009. Published studies of informant-rated personality traits in AD patients were identified. Studies that mapped changes in traits from the five-factor model of personality which includes factors for Neuroticism, Extraversion, Openness, Agreeableness and Conscientiousness, were selected for analysis. The change in each of these five traits was calculated as the mean difference in score before and after the diagnosis of AD. There was a mean increase in Neuroticism of 10-20 T scores (equivalent to 1-2 SD), a decrease of the same magnitude in Extraversion, consistently reduced Openness and Agreeableness, and a marked decrease in Conscientiousness of about 20-30 T scores (equivalent to 2-3 SD). These changes were systematic and consistent. Particularly striking was the similarity of both the magnitude and direction of change in all studies reviewed. Conscientiousness and Neuroticism are the personality traits that exhibit the most change in dementia. These traits might be useful early markers of dementia.