Neuroticism Traits Selectively Impact Long Term Illness Course and Cognitive Decline in Late-Life Depression

Abstract

Neuroticism is a broad construct that conveys a predisposition to experience psychological distress and negative mood states. Vulnerability to stress (VS) is one neuroticism trait that has been linked to worse mood and cognitive outcomes in older adults. We hypothesized that elevated VS would be associated with worse illness course and cognitive decline in older adults with late-life major depression (LLD). Participants were enrolled in the Neurocognitive Outcomes of Depression in the Elderly (NCODE), a longitudinal investigation of the predictors of poor illness course and cognitive decline in LLD. Participants were followed upwards of 10 years. NCODE operates in a naturalistic treatment milieu. 112 participants aged 60 and older with a current diagnosis of major depressive disorder. Treatment response was assessed at least every 3 months and more often if clinically needed. Participants also completed the NEO Personality Inventory-Revised (NEO PI-R) and an annual cognitive examination. Neuroticism traits from the NEO PI-R included anxiety, depression, anger-hostility, self-consciousness, impulsivity, and VS. Higher neuroticism traits of VS, impulsivity, anger-hostility, and anxiety were associated with worse treatment response over time. High VS was the only neuroticism trait significantly associated with cognitive functioning. High VS negatively influenced the rate of global cognitive decline over time. Individual personality traits within the neuroticism dimension are associated with treatment resistance and cognitive impairment in LLD. It remains to be seen whether these individual traits are associated with different neurobiological substrates and clinical characteristics of LLD.