Do depressive symptoms at time of diagnosis affect the course of dementia over one year?

Background Depressive symptomatology has long been associated with dementia. The exact form of this association (e.g. whether depression is a risk factor and/or a prodrome) is uncertain. While much research has gone into confirming this link, there has been little investigation into the effects of depression on dementia progression after diagnosis. The aim of this study is to investigate the relationship between depressive symptomatology at dementia diagnosis and cognitive and behavioural decline over a one year period as represented by clinical evaluations. Methods In 375 rural and remote patients who had been diagnosed with mild cognitive impairment (MCI), Alzheimer’s disease (AD), or non‐AD dementia, the Center for Epidemiological Studies Depression Scale (CES‐D) was completed at first visit to assess depressive symptomatology. The same cohort was evaluated for cognitive and behavioural decline through the completion of five clinical tests performed at first visit and at a one year follow up. Cognitive decline was assessed using the Mini Mental Status Examination (MMSE), Clinical Dementia Rating Scale (CDR), and two subsets of the Neuropsychiatric Inventory (NPI‐S and NPI‐D). Functional decline was assessed using the Functional Activities Questionnaire (FAQ). Correlations were examined between CES‐D score and change in cognitive and functional scores over one year in the subgroups of Patients with all types of dementia or mild cognitive impairment (ATD, N=375 ), Alzheimer’s type dementia (N=187), and Mild Cognitive Impairment (=74). Results No significant correlations were observed between cognitive or functional decline and baseline depressive symptomatology. Conclusion Severity of depressive symptomatology at the time of diagnosis does not predict severity of cognitive or functional decline at one year in patients with dementia or mild cognitive impairment.