Neurocognitive profiles in older adults with and without major depression

To delineate the differences between older persons with and without a diagnosis of major depression.

Participants were recruited from three outpatient clinics serving older patients at St Michael's Hospital. To be included in the study, participants had to speak English and have no evidence of significant sensory deficits that would interfere with neuropsychological testing. Participants were excluded if they had active delirium, active CNS disease (including dementia), active substance abuse, unstable medical disease, recent ECT treatment and a current/past diagnosis of a psychotic disorder. The diagnosis of major depression was made by qualified professionals in accordance with established guidelines. Participants were administered structured measures assessing global cognition, medical co-morbidity, subjective memory complaints, mood and detailed neurocognitive testing evaluating working memory, attention and speed of processing. Differences between depressed and non-depressed subjects with respect to these measures were analyzed using analysis of variance (ANOVA).

Thirty-six participants were included in this study. The depressed (n = 17) and non-depressed (n = 19) groups were well matched in terms of age, education, medical co-morbidity and mini-mental state exam (MMSE) score. While the depressed subgroup had significantly higher subjective memory, language and cognitive complaints, there were no significant differences observed between the two subgroups on measures of memory and learning, attention and speed of information processing, fine motor dexterity and verbal fluency.

This study suggests that while significant depressive symptoms are strongly associated with increased cognitive complaints, they are not associated necessarily with objective cognitive impairment.