Relation between neuritic plaques and depressive state in Alzheimer's disease

Background: To investigate for the first time in a prospective study the relationship between depressive state and the neuropathological hallmarks of Alzheimer's disease, using a scale for depressive symptoms in dementia, while controlling for clinical severity of dementia. Method: Within the framework of a prospective longitudinal study of depression in Alzheimer's disease, patients with dementia underwent a clinical evaluation every six months during the last years of their lives, using the Cornell scale for depression in dementia to assess depressive symptoms and using the Functional Assessment Staging scale to control for clinical severity of dementia. The brains of 43 Alzheimer patients were obtained. The last clinical evaluations prior to death together with post-mortem neuropathology measures were analysed. Results: We found a correlation between the Cornell scores and the sum score for the density of neuritic plaques in the entire cortex (p = 0.027), and even stronger in the temporal cortex (p = 0.012). The observed correlations were independent of sex, age of death, clinical dementia severity and duration of Alzheimer's disease. Conclusions: This study shows a positive relationship between depressive state at time of death and the presence of neuritic plaques in Alzheimer's disease, which is independent of the clinical severity of dementia.