Apathy: a separate syndrome from depression in dementia? A critical review.

Apathy and depression are the most prevalent neuropsychiatric symptoms in Alzheimer's disease and mild cognitive impairment. Despite much research on apathy and depression in dementia, the nosological position of apathy as a separate syndrome from depression remains debated. This literature review provides a critical analysis of the areas of clinical manifestation, symptomatology, assessment, prevalence and neuropathology. Evidence does not provide a clear view of the nosological position of apathy in dementia for symptoms and neuropathology. However, the ambiguity of the evidence may be attributed in large part to a lack of clarity in definition and etiology, clinical criteria and assessment overlap. Given the evidence, it is concluded that the argument in favor of apathy as a separate syndrome from depression in dementia is persuasive. Reaching a consensus on the definition and nosological position of apathy within dementia is vital to provide patients and caregivers with the support they require, increase understanding of risk factors, and enable comparisons across research and practice.