Apathy and depression are the two most frequent neuropsychiatric symptoms in Alzheimer's disease (AD) and related disorders. Whereas neuroimaging studies have shown different neural pathways for these two symptoms, a clinical overlap between apathy and depression is frequently described.

To describe the prevalence of apathy and depression among elderly subjects with or without dementia criteria using specific diagnostic criteria for apathy and depression.

Subjects from an ongoing cross-sectional study were recruited in 4 centers (France, Indonesia, Spain, Argentina). Apathy and depression were assessed using the diagnostic criteria for apathy and for depression. Additionally, the apathy and dysphoria domains of the NPI-C (Neuropsychiatric Inventory-Clinician), as well as the 12 domains of the original NPI (Neuropsychiatric Inventory) were assessed.

431 subjects (mean age=74.6 ± 10.4 ; gender=♂ 29%) were recruited (France=100, Spain=90, Indonesia=182, Argentina=79). Among them, 25% were healthy elderly subjects, 9% had a diagnosis of MCI (Mild Cognitive Impairment), 46% had a diagnosis of dementia (including AD, Lewy body, vascular, mixed and fronto-temporal dementia). In the overall population, the prevalence of apathy and depression were respectively 41% and 25%. More specifically, the prevalence of apathy and depression in the AD sample were 67% and 25%.

Diagnostic criteria for apathy and depression, as well as the NPI-C, are recent assessment methods in the field of dementia, developed to increase the accuracy of the clinical evaluation of BPSD. It is therefore critical to propose multicenter observational studies comparing these new tools with classical assessment methods.