OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: Conscientiousness and Neuroticism are the personality traits that 
exhibit the most change in dementia. These traits might be useful early markers 
of dementia.