Background: Apathy and depression are the most common neuropsychiatric features in Alzheimer's disease (AD). The clinical and functional specific correlates of these syndromes are not well known independently from cognitive deficits and other behavioral disturbances.
Material and methods: Six hundred and eighty-six patients diagnosed with possible or probable AD were included in a prospective multicenter study (REAL-FR). They had an assessment of their cognitive and functional status. Neuropsychiatric symptoms were assessed with the Neuropsychiatric Inventory (NPI) and caregiver's burden was measured with Zarit's Burden Scale.
Results: A majority of patients at any stage of the disease presented with one or several behavioral and psychological disturbances. Apathy concerned 43% of patients and, with or without depression, was associated with more pronounced deficits in global cognition, everyday life and instrumental abilities, nutritional status and with a higher burden level. A high level of psychotropic prescription, especially with antidepressant, was observed in patients with apathy. In a multivariate analysis taking into account the cognitive and functional variables of AD, apathy and depression were the only significant predictors of psychotropic prescription.
Conclusion: Some negative neuropsychiatric symptoms such as apathy and depression have a specific relation with functional and therapeutic outcomes of AD, independently from cognitive status. Further studies are needed to establish if apathy represents a particularly severe phenotype of AD.