Depression and apathy in dementia: Same syndrome or different constructs? A critical review
Introduction
Depression and dementia are common in older people and their association is very complex. Depressive disorders, both major depression and other less severe, but nonetheless clinically significant depressions, are frequent comorbidities, components, or complications of dementia. Apathy is one of the most common symptom in dementia, but despite its high prevalence, has received much less attention in scientific literature, than depression itself. So far the nosological position of apathy remains obscure, even if some of the most recent studies support the notion that it is a specific neuropsychiatric syndrome which differs from depression, but is difficult to discriminate in dementia, because it is often exists as a comorbidity with depression (Starkstein et al., 2001).
This review examines the specific clinical diagnostic criteria and neurobiological correlates of apathy and depression in AD.
Section snippets
Epidemiology
More than half of the patients with dementia suffer from one or more depressive symptoms, such as anxiousness, sadness, irritability, agitation or psychomotor retardation, sleep problems, diminished social activity, or loss of interest (Lyketsos and Lee, 2004). Some of the most recent studies from clinical settings suggest that the prevalence of major depressive episode in AD is 20–25%, while other depressive syndromes and minor depression afflict an additional 20–30% of patients with AD (Olin
Diagnosis
The diagnosis of depression in dementia is not an easy task, and it is even more difficult to differentiate apathy from depression because of a substantial overlap in the key symptoms. Depression involves considerable emotional distress, evidenced by tearfulness, sadness, anxiety, agitation, insomnia, anorexia, feelings of worthlessness and hopelessness, and recurrent thoughts of death. According to the DSM-IV-TR (American Psychiatric Association, 2000) a principal symptom of depression may be
Depression and apathy: overlaps and differences
Differentiating apathy from depression in dementia is difficult because of their frequent association and to a substantial overlap in key symptoms. The modern concepts of apathy and depression both share the prediction of “reduced volition” (in the etymological sense of “acting an intention”), which automatically implies a phenomenological overlap. Loss of interest and motivation is, in fact, a conspicuous symptom of both syndromes. Also vegetative symptoms of depression, such as psychomotor
Neurobiological correlates
Differences between apathy and depression in dementia have been demonstrated also on neurobiological basis. Hypoperfusion or hypoactivity in frontal, parietal, and temporal regions are identified in both apathy and depression (Craig et al., 1996, Ebmeier et al., 1997, Starkstein et al., 1997, Lopez et al., 2001). However, apathy is more related with hypoperfusion in regions that are involved in frontal–subcortical networks (Landes et al., 2001).
Apathy in AD is strongly associated with
Conclusion
Apathy is a primary deficit in motivation that should be distinguished from cognitive decline and depression. Apathy is extremely common in dementia and most of the time coexists with depression in the same patient, but its presence should be considered during the routine course of a neuropsychiatric evaluation without ascribing it to depression itself. In order to distinguish the two syndromes, symptoms of sadness and feelings of helplessness, hopelessness, and worthlessness prove to be
Conflict of interest statement
None.
Acknowledgement
To the proofreader Marzia Pellegrini.
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