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Symptom Dimensions of Depression and Apathy and Their Relationship With Cognition in Parkinson’s Disease

Published online by Cambridge University Press:  16 October 2017

Sarah M. Szymkowicz
Department of Clinical & Health Psychology, College of Public Health & Health Professions, University of Florida, Gainesville, Florida
Vonetta M. Dotson
Department of Clinical & Health Psychology, College of Public Health & Health Professions, University of Florida, Gainesville, Florida Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida
Jacob D. Jones
Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California - Los Angeles, Los Angeles, California
Michael S. Okun
Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida Center for Movement Disorders & Neurorestoration, College of Medicine, University of Florida, Gainesville, Florida
Dawn Bowers*
Department of Clinical & Health Psychology, College of Public Health & Health Professions, University of Florida, Gainesville, Florida Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida Center for Movement Disorders & Neurorestoration, College of Medicine, University of Florida, Gainesville, Florida
Correspondence and reprint requests to: Dawn Bowers, Department of Clinical & Health Psychology, College of Public Health & Health Professions, University of Florida, P.O. Box 100165, Gainesville, FL 32610-0165. E-mail:


Objectives: Both depression and apathy, alone and in combination, have been shown to negatively affect cognition in patients with Parkinson’s disease (PD). However, the influence of specific symptom dimensions of depression and apathy on cognition is not well understood. The current study investigated the relationship between symptom dimensions of depression and apathy, based on factors identified in Kirsch-Darrow et al. (2011), and memory and executive function in PD. Methods: A sample of 138 non-demented individuals with PD (mean age=64.51±7.43 years) underwent neuropsychological testing and completed the Beck Depression Inventory, 2nd Edition, and Apathy Scale. Separate hierarchical regression models examined the relationship between symptom dimensions of depression and apathy (“pure” depressive symptoms, “pure” apathy, loss of interest/pleasure [anhedonia], and somatic symptoms) and three cognitive domain composites: immediate verbal memory, delayed verbal memory, and executive function. Results: After adjusting for general cognitive status and the influence of the other symptom dimensions, “pure” depressive symptoms were negatively associated with the delayed verbal memory composite (p<.034) and somatic symptoms were positively associated with the executive function composite (p<.026). No symptom dimensions were significantly related to the immediate verbal memory composite. Conclusions: Findings suggest that specific mood symptoms are associated with delayed verbal memory and executive function performance in non-demented patients with PD. Further research is needed to better understand possible mechanisms through which specific symptom dimensions of depression and apathy are associated with cognition in PD. (JINS, 2018, 24, 269–282)

Research Articles
Copyright © The International Neuropsychological Society 2017 

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