Clinical outcomes of older depressed patients with and without comorbid neuroticism

Neuroticism is a psychological construct that includes tendency to exhibit negative affect (NA), having poor stress tolerance and being at risk for depression and anxiety disorders. The consequences of neuroticism in the elderly adults are understudied. We hypothesized that older depressed patients with comorbid neuroticism at baseline would have worse mood and cognitive outcomes compared with older depressed patients without neuroticism.

One hundred and ten older depressed adults completed baseline self-reports of depression and the NEO-Personality Inventory as a measure of neuroticism, were administered a battery of cognitive tests annually and were seen by a study psychiatrist who assessed patients using the Montgomery Åsberg Depression Rating Scale (MADRS) and treated patients with antidepressants using an established treatment guideline. Patients were followed as clinically indicated for up to three years. We measured remission (defined as MADRS score ≤ 6) rates at one year as a categorical outcome. In addition, we used Cox proportional hazard models to examine the relationship between neuroticism and change in MADRS and cognitive score over time.

Non-remitters (30%) at one year had higher scores in total neuroticism (TN), vulnerability to stress (VS), and NA. Over three years, time to achieve remission was associated with higher TN, higher VS, and greater NA. In analyses controlling for baseline cognitive score, age, sex, and education, VS was associated with baseline to two-year change in cognition.

Presence of neuroticism in older depressed patients treated with medication is associated with poor mood outcomes and may indicate increased risk of cognitive decline.