Depression in patients with moderate Alzheimer disease: a prospective observational cohort study

Syndromes of depression are frequently concomitant with Alzheimer disease (AD), although often inaccurately diagnosed and/or treated. This prospective, multicenter, observational, cohort study assessed baseline data and 6-month disease changes in moderate AD patients (n=1249) from Spain. Baseline Cornell Scale for Depression in Dementia (CSDD) scores defined 2 cohorts (depressive ≥8 or nondepressive <8). Fewer patients had baseline Diagnostic and Statistical Manual for Mental disorders-IV depression diagnosis (38.9%) than CSDD ≥8 (55.6%). Analysis of diagnostic accuracy of the CSDD versus the Diagnostic and Statistical Manual for Mental disorders-IV criteria showed an optimal cutoff score of ≥12. However, the predefined CSDD cutoff score showed subsyndromal depressive symptomatology associated with lower functionality, worse neuropsychiatric symptomatology, increased caregiver distress, and greater 6-month functional and clinical impairments. Cognition (baseline and 6-month progression) was not significantly associated with depressive symptomatology. Depressive patients received more antidepressive and/or antipsychotic treatments, showing CSDD and Neuropsychiatric Inventory Questionnaire (severity and caregiver distress) 6-month improvements but maintaining doubled scores than nondepressive patients. In conclusion, CSDD ≥8 identified depressive symptomatology in moderate AD patients, significantly associated with excessive neuropsychiatric symptoms and functional, but not cognitive, 6-month deterioration. The health effects over patients and caregivers, alongside the finding that most patients remained depressive after 6 months, demand accurate diagnostic tools and effective treatments for depression in AD.