The relationships among depression, personality factors, stress, and cognitive decline
in the elderly are complex. Depressed elders score higher in neuroticism than nondepressed
older individuals. Independently, the presence of neuroticism and the number of stressful
life events are each associated with worsening cognitive decline in depressed older
adults. Yet little is known about combined effects of changes in neuroticism and changes
in stress on cognitive decline among older depressed adults.
Longitudinal observational study.
Academic Health Center.
The authors examined 62 participants in the Neurobiology of Late-life depression (NBOLD)
study to test the hypothesis that, compared with older depressed subjects who experience
improved neuroticism and lower psychosocial stressors over time, those with worsening
neuroticism and greater psychosocial stressors will demonstrate more cognitive decline.
The authors measured neuroticism using the NEO-Personality Inventory-Revised at baseline
and 1 year. Study psychiatrists measured depression using the Montgomery-Ǻsberg Depression
Rating Scale. At annual assessments, subjects reported the number of psychosocial
stressors in the prior year and completed a neuropsychological evaluation. Participants
completed a detailed neuropsychological battery at baseline and annually over 3 years.
The battery included a test of delayed story memory (Logical Memory-2 or LMII). The
outcome 3-year change in cognitive scores was regressed against 3-year change scores
of neuroticism and number of psychosocial stressors, plus their interaction, while
adjusting for sex, age, race, education, baseline cognitive score, and 3-year change
in MADRS score as covariates.
In multivariable linear regression analysis with the above covariates, the interaction
effect of 3-year change in Total Neuroticism score and 3-year change in Total Stressors
on change in LMII performance was statistically significant (B = −0.080[95%CL: −0.145
to −0.015], T = −2.48, df = 52, p = 0.017). Further exploration of this finding showed
that 1) when total stressors increased by 2 or more over 3 years, LMII change was
inversely associated with neuroticism change; and 2) when neuroticism improved less,
LMII change score was inversely associated with total stressor change. There were
no other significant interactions between stress and neuroticism on cognition.
Our findings document the importance of tracking change in neuroticism and monitoring
psychosocial stress over the long-term course of treatment in geriatric depression.
Both factors exert important combined effects on memory over time. Future studies
in larger samples are needed to confirm our results and to extend them to examine
both cognitive change and development of dementia.