Personality Correlates of Functional Status in Patients With Early-Stage Behavioral Variant Frontotemporal Dementia.

Abstract (English)

BACKGROUND AND OBJECTIVES: Functional impairment emerges early in behavioral variant frontotemporal dementia (bvFTD), significantly disrupting independence and quality of life. Although personality change is a core feature of bvFTD, its relationship with everyday functioning remains incompletely understood. This study aimed to characterize disease-related changes in personality and examine the associations of premorbid and current personality traits with functional status in early-stage bvFTD. METHODS: In this retrospective study conducted at the University of California, San Francisco, Fein Memory and Aging Center, patients who met criteria for at least possible bvFTD, had a Mini-Mental State Examination score >18, and an available knowledgeable informant were evaluated at their earliest visit. Informants completed the Big 5 Inventory to assess premorbid and current personality. Functional status was evaluated using the informant-rated Functional Activities Questionnaire (FAQ), measuring instrumental activities of daily living. Linear regression was used to examine associations between premorbid personality and FAQ scores, and hierarchical regression was used to evaluate whether current personality explained variance beyond demographics and premorbid traits. Multiple comparisons were addressed using the Benjamini-Yekutieli procedure. RESULTS: The sample included 111 patients with bvFTD (mean age, 63.03 years; 33.33% female). Substantial disease-related personality changes were observed across all traits, including marked reductions in conscientiousness, openness, extraversion, and agreeableness, alongside increased neuroticism (all <i>p</i> < 0.001). Premorbid personality was not associated with FAQ scores. Addition of current personality significantly increased explained variance (Δ<i>R</i>² = 0.371; <i>F</i> change (5, 98) = 12.07; <i>p</i> < 0.001). The fully adjusted model explained 39.72% of FAQ variance (95% CI [0.316-0.597]; adjusted <i>R</i>² = 0.323). Higher current conscientiousness was independently associated with lower FAQ scores, indicating better functional status (<i>B</i> = -0.51, <i>&#x3b2;</i> = -0.52; 95% CI [-0.704 to -0.317]; <i>p</i> < 0.001), and remained significant after multiple-comparison correction. DISCUSSION: Disease-related reductions in conscientiousness may reflect executive and motivational dysfunction directly relevant to real-world disability. Personality measures may provide clinically meaningful insight into functional risk and complement traditional severity indices in bvFTD. Limitations include the cross-sectional design, retrospective assessment of premorbid personality, and shared-informant reporting of personality and functional status. Longitudinal studies incorporating performance-based functional measures are needed to validate these findings.