Abstract

Subsyndromal Symptomatic Depression (SSD), or subthreshold depression, affects roughly 15% of community-dwelling older adults and puts them at increased risk for developing Major Depressive Disorder (MDD), which represents a risk factor for Alzheimer’s Disease (AD) and may expedite disease progression. While the relationship between MDD and AD has been well established, the interaction between SSD and cognitive functioning has not been explored in depth. Further, clinicians have long postulated that depression is not a monolithic disorder but rather a group of disorders which are heterogeneous in onset, symptoms, course, and treatment. One hundred and six participants, 65 and older were recruited as part of the Adventist Health Study-2 Cognition and Neuroimaging Substudy and underwent comprehensive neuropsychological testing. Results of an independent samples t-test revealed that individuals who met criteria for SSD performed significantly worse in the immediate recall over five learning trials on the Rey Auditory Verbal Learning Test (RAVLT) than individuals who did not report depressive symptomatology. Further, a hierarchical regression analysis evidenced that depressive symptoms categorized as “hopelessness”, “dysphoric mood”, and “cognitive impairment” were significant predictors of global cognitive functioning within our SSD sample. These findings suggest that SSD— specifically when symptoms are related to “hopelessness”, “dysphoric mood”, and “cognitive impairment”—has a significant impact on cognition. Future research should utilize a longitudinal study design that examines conversion rates of SSD to MCI/dementia to conclude that SSD represents a clinical marker of dementia. If identified as a viable clinical marker, early detection and treatment of SSD could potentially prevent worsening of depression symptoms as well as delay—or even curb— the manifestation of MCI/Dementia in later life.

LLU Discipline

Psychology

Department

Psychology

School

School of Behavioral Health

First Advisor

Grace J. Lee

Second Advisor

Colleen A. Brenner

Degree Name

Doctor of Psychology (PsyD)

Degree Level

Psych.D.

Year Degree Awarded

2020

Date (Title Page)

9-2020

Language

English

Library of Congress/MESH Subject Headings

Depression--In old age; Alzheimer’s Disease

Type

Doctoral Project

Page Count

68 p.

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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