Depression and apathy in dementia: same syndrome or different constructs? A critical review.

Apathy is the most common neuropsychiatric syndrome in Alzheimer's disease (AD) affecting 19-76% of patients, but is difficult to distinguish from depression, because of the frequent comorbidities and a considerable overlap in key symptoms. A structured clinical interview and a specific set of diagnostic criteria to diagnose apathy in dementia have been recently validated, but so far its nosological position is still a debated issue, even if several studies tend to consider apathy a discrete and specific syndrome. The pathophysiology of apathy in neuropsychiatric disorders is still unknown, however, recent studies suggest that an important role is played by dysfunctions of the frontal lobe and basal ganglia. Both apathy and depression can have a negative impact on the progression of AD, therefore, an accurate differential diagnosis is fundamental to reach an appropriate family education and to obtain a possibly effective treatment.