Associations between personality traits and cognitive function in multiple sclerosis and neuromyelitis optica spectrum disorder: A cross-sectional study

Abstract

Background: Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are chronic demyelinating diseases of the central nervous system frequently associated with cognitive impairment (CI). Although both disorders share overlapping neurological manifestations, they differ substantially in underlying pathophysiology and disease course. Despite the clinical relevance of personality traits and cognition in chronic neurological disorders, the relationship between cognitive function and the five major personality domains remains insufficiently characterized in MS patients. Moreover, this relationship has not yet been adequately investigated in NMOSD patients. This study aimed to explore the associations between personality traits and cognitive function in MS patients and NMOSD patients. Methods: This cross-sectional study incorporated 100 MS patients and 53 NMOSD patients between March and November 2024 in Isfahan, Iran. The Symbol Digit Modalities Test (SDMT) and Mini-Mental State Examination (MMSE) were used to assess cognitive performance. Personality traits were evaluated using the NEO Five-Factor Inventory (NEO-FFI). Hierarchical regression models determined significant predictors of cognitive performance. Results: In multivariable analyses, Conscientiousness was significantly associated with cognitive performance in both groups. In MS patients, Conscientiousness was independently associated with higher SDMT (B = 0.25, p = 0.003). Among NMOSD patients, Conscientiousness was significantly associated with higher SDMT (B = 0.45, p < 0.001) and MMSE (B = 0.09, p = 0.035). Additionally, Agreeableness was inversely associated with SDMT in NMOSD patients (B = -0.38, p = 0.009). Conclusion: These findings indicate that some personality traits, particularly Conscientiousness, are associated with cognitive performance in MS and NMOSD. While these associations have been identified in MS, they are preliminary findings in NMOSD and highlight the clinical relevance of personality traits in interpreting cognitive assessments and supporting more personalized approaches to cognitive care.