ABSTRACT
OBJECTIVE: The aims of this study were to examine: (1) the relationship between apathy and disability in late-life depression, and (2) the functional significance of improvement in apathy following escitalopram treatment in terms of its relationship to disability. METHODS: Subjects were 71 non-demented elderly with non-psychotic major depression. After a 2-week single-blind placebo period, subjects who had Hamilton Depression Rating Scale (HDRS) ≥ 18 received escitalopram 10 mg daily for 12 weeks. Apathy and disability were assessed with the Apathy Evaluation Scale (AES) and the World Health Organization Disability Assessment Scale II (WHODAS), respectively. These measures and the HDRS were administered at baseline and again following 12 weeks of treatment. RESULTS: At baseline, 38% of depressed subjects had significant apathy (AES ≥ 36.5). Severity of apathy at baseline significantly correlated with severity of disability. In a multivariate regression model, baseline severity of apathy, but not the overall depressive syndrome (HDRS), significantly correlated with baseline disability. Following escitalopram treatment, improvement in apathy significantly correlated with improvement in disability measures, while change in the rest of the depressive syndrome did not. The overall change in apathy and disability in response to escitalopram treatment was significant but small. CONCLUSION: Apathy is common in late-life depression and is associated with disability above and beyond the influence of other depressive symptoms. Given the strong relationship between apathy and disability, understanding the neurobiology of apathy and developing treatments for apathy may improve the functional outcomes of late-life depression.
Subject(s)
Apathy , Citalopram/administration & dosage , Depressive Disorder, Major , Depressive Disorder/diagnosis , Aged , Antidepressive Agents, Second-Generation/administration & dosage , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/drug therapy , Depressive Disorder, Major/psychology , Diagnostic and Statistical Manual of Mental Disorders , Disability Evaluation , Female , Geriatric Assessment , Humans , Late Onset Disorders , Male , Psychiatric Status Rating Scales , Statistics as Topic , Treatment OutcomeABSTRACT
OBJECTIVE: Apathy is prevalent in late-life depression and predicts poor response to antidepressants, chronicity of depression, disability, and greater burden to caregivers. However, little is known about its neurobiology. Salience processing provides motivational context to stimuli. The aim of this study was to examine the salience network (SN) resting-state functional connectivity (rsFC) pattern in elderly depressed subjects with and without apathy. METHODS: Resting-state functional MRI data were collected from 16 non-demented, non-MCI, elderly depressed subjects and 10 normal elderly subjects who were psychotropic-free for at least 2 weeks. The depressed group included 7 elderly, depressed subjects with high comorbid apathy and 9 with low apathy. We analyzed the rsFC patterns of the right anterior insular cortex (rAI), a primary node of the SN. RESULTS: Relative to non-apathetic depressed elderly, depressed elderly subjects with high apathy had decreased rsFC of the rAI to dorsal anterior cingulate and to subcortical/limbic components of the SN. Depressed elderly subjects with high apathy also exhibited increased rsFC of the rAI to right dorsolateral prefrontal cortex and right posterior cingulate cortex when compared to non-apathetic depressed elderly. CONCLUSIONS: Elderly depressed subjects with high apathy display decreased intrinsic rsFC of the SN and an altered pattern of SN rsFC to the right DLPFC node of the central executive network when compared to elderly non-apathetic depressed and normal, elderly subjects. These results suggest a unique biological signature of the apathy of late-life depression and may implicate a role for the rAI and SN in motivated behavior.
