Cognitive and Demographic Determinants of Dementia in Depressed Patients with Subjective Memory Complaints

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Abstract
Previous studies showed that late-life depression with subjective memory complaints (SMC) may be associated with an increased risk of developing dementia. However, not all such patients have cognitive decline. The aim of this longitudinal study was to identify possible clinical determinants of progressive deterioration in depressed elderly patients with SMC. Forty-one consecutive patients referred to a memory clinic because of persistent SMC were investigated and received an ICD-10 diagnosis of mild to moderate depression. Over a mean follow-up period of 15 months, 9 of them (22%) developed dementia. Statistical analysis included Mann-Whitney U and Fisher's exact tests as well as univariate and multivariate logistic regression analyses to assess the relationship between cognitive decline and clinical, demographical and neuropsychological characteristics at baseline. Age at baseline was associated with subsequent dementia, and performance on immediate verbal prose recall and a visual organization test at the initial assessment were worse in those who showed cognitive decline. In a multivariate model, age and immediate recall predicted 32.7% of the cognitive variability, with an additional 2.4% when a visual organization test was added. There was no correlation between cognitive performance and severity of depression at baseline. The study was limited by a small sample size, the nondistinction of depressive subtypes and the absence of a formal neuropsychological assessment on follow-up. Impairment of the executive component of working memory as well as limited access to visual knowledge may predict cognitive deterioration in depressed patients with subjective memory complaints.