Predictive role of Neuroticism and Conscientiousness in conversion from mild cognitive impairment to Alzheimer’s disease

Objectives: Mild cognitive impairment (MCI) is considered a prodromal stage of Alzheimer’s disease (AD) with a 10–15% annual conversion rate. This study aimed to explore the role of the personality traits Conscientiousness and Neuroticism in predicting conversion from MCI to AD, and worsening dementia severity. Method: This retrospective, longitudinal study enrolled 69 older adults diagnosed with MCI. At the baseline assessment, the outcomes of interest were Folstein Mini-Mental State Exam (MMSE), Lawton Brody Instrumental Activities of Daily Living scale (LB-IADL), and Clinical Dementia Rating Sum of Boxes (CDR-SB). Results: Lower baseline Conscientiousness significantly predicted conversion from MCI to probable AD (OR =0.945, p = 0.043). Higher baseline Conscientiousness was also associated with better cognitive performance at follow-up, as indicated by higher MMSE scores (B = 0.158, p = 0.001) and lower CDR-SB scores (B = −0.083, p = 0.008). In contrast, higher baseline Neuroticism significantly predicted poorer functional outcomes, reflected by higher LB-IADL scores at follow-up (B = 0.296, p = 0.006). Conclusion: This study replicates prior findings by indicating that Conscientiousness and Neuroticism predict disease course in a clinic sample, using measures of disease transition, cognitive worsening and decline in instrumental ADLs. Conscientiousness is a brief measure that can be applied routinely in the real-world clinic setting.