P
REDICTORS OF
D
EPRESSION WITHIN THE
C
AREGIVERS
OF
D
EMENTIA
P
ATIENTS
Melissa G. Sneed
Faculty Co-Authors and Sponsors: Nancy H. Wrobel and Robert W. Hymes
Department of Behavioral Sciences, University of Michigan-Dearborn
Abstract
The Aging, Demographics, and Memory Study (ADAMS) is the first population-based study of dementia in
the United States to include subjects from all regions of the country. A sample of 856 individuals age 70 or
older received an extensive in –home clinical and neuropsychological assessment to determine a diagnosis of
normal, ‘cognitive impairment, not demented’ (CIND), or demented. Variables associated with patient’s
cognitive levels and the caregivers’ strains were assessed. Specific measures in this study included
socio-demographic variables; patient’s cognitive levels were measured using the short form of the Informant
Questionnaire on Cognitive Decline in the Elderly (IQCODE), Mini-Mental State Exam (MMSE),Dementia
Severity Rating Scale (DSRS) and activities of daily living from the Blessed Dementia Scale. Caregivers
completed an abbreviated form of the Center for Epidemiologic Studies Depression Scale (CES-D), and
The National Institute on Aging (NIA) funded the Aging, Demographics, and Memory Study
(ADAMS), which is a supplement to the Health and Retirement Study (HRS). The HRS is sponsored by the
NIA (grant number NIA U01AG009740) and is conducted by the University of Michigan. ADAMS has
provided an opportunity for conducting in-depth investigations related to the impact of dementia on formal
health care utilization, informal caregiving, and the total societal costs of this care. ADAMS not only
gathered information on the participants, but also on the caregivers (HRS, 2007).
This study initially originated when the HRS formed a partnership with a research team from Duke
University, led by Brenda Plassman, director of the Epidemiology of Dementia Program. This partnership
was created to conduct in-person clinical assessments for dementia on selected HRS respondents. This
research is the first of its kind to conduct in-home assessments of dementia in a national sample that is
representative of the U.S. elderly population. The field work began in August 2001 and was completed by
March 2005 (HRS, 2007).
The study reported here focuses on caregivers of the elderly and possible predictors of depression in
caregivers. Dementia occurs in 1% of people age 65-69 and around 24% of people 85 or older (Alzheimer’s
disease International, 2000). Dementia patients may endure the loss of their functional and mental status. The
decline in cognitive functioning, the ability to perform activities of daily living (ADLs) [such as bathing and
dressing], and the instrumental activities of daily living (IADLs) [such as housework and paying bills] adds to
the amount of work performed by the caregiver (Sherwood, Given, Given, & Von Eye, 2005).
Caregivers play an important role in the life of people they care for. Studies have shown an increase of
knowledge in the medical fields contribute to an increase in the lifespan of the elderly population. The
demand for caregivers will also expand (Kang, 2006). Furthermore, the care for the caregiver is an essential
factor in society and should be acknowledged since the population of the elderly is on the rise. It’s also an
important factor in society that caregivers receive care, since they are the ones maintaining the elderly
community (Kang, 2006).
Estimates show that between 46% and 83% of dementia caregivers experience depression
(Alspaugh, 1999). Emotional stress is found to be a major factor among Dementia caregivers. This study
seeks to identify the predicting factors of depression in caregivers of dementia patients. Previous research has
found that caregivers’ depressive symptoms indicate a mood disturbance that results from the demands
impact of actual cognitive and functional impairment in the care recipient on the caregiver, but also examines
the impact of the caregivers’ perception of decline and reported strain.
Method
Participants
The participants consisted of 1770 individuals that were a random sample taken from the national
representative Health and Retirement Study (HRS) sample. Out of the 1770 participants, there were 856
subjects (a response rate of 56%) who completed the initial assessment. There were a total of 227 subjects
(12.8%) who died before an initial assessment could be completed. There were 687 subjects (38.8%) who
declined an assessment or did not participate for other reasons such as no informant or an illness. The sample
was composed of participants within the U.S. Census Region.
Participants were comprised of 501 females (59%) and 355 males (41%). Ethnicity was comprised of 84
Hispanic (10%), 159 Black, non Hispanic (19%), and 613 White, non Hispanic (72%). Their ages ranged
from 70 to 110 (M = 81.78, SD = 7.22). The number of subjects participating included 120 from the Northeast (14%), 167 from the Midwest (19%), 239 from the South Atlantic (28%), 163 from the South Central (19%)
and 167 from the West (19%). There are 763 participants (89%) who resided in the community and 93
participants (11%) resided in nursing homes.
This study also included data on 746 informants. They were comprised of 189 males (25%) and 540
females (72%). The informants’ ages ranged from 20 to 95. There are 375 informants (50%) who live with
the participants. Of the 746 informants, ethnicity was comprised of 548 White/Caucasian (74%), 129
Black/African American (17%) and 46 other (6%) with 23 missing data (3%).
Measures
Abbreviated Center for Epidemiologic Studies Depression Scale (CES-D): Developed by Radloff (1977). This scale contains 5 items, with 2 of the questions recoded in order for all responses to reflect scores
consistent with depression. The responses were then totaled to determine their final score. It is a quick
self-test and measures depressive feelings and behavior. Research by Radloff (1977) shows the Center of
Epidemiologic Studies Depression (CES-D) Scale is the most frequently used to determine depression in
caregivers. Findings have determined many patterns of depressive symptomology in caregivers as well as
dementia patients (Alspaugh, 1999).
Mini Mental State Exam (MMSE): Developed by Folstein, Folstein, and Fanjiang, (2001). The MMSE is a test that figures prominently in research on dementia (Teri, 1991). This scale was developed as a screening
tool which assesses cognitive functioning. The MMSE consists of 22 items (orientation (10), language (8)
and one item of each: registration, memory, spelling backward, and construction) with a maximal obtainable
score of 30. . The MMSE score is obtained from the summed scores of all items. Any score over 27 is
normal; scores of 20-26 indicates some cognitive impairment; 10-19 suggests moderate to severe cognitive
impairment; below 10 indicates very severe cognitive impairment. The validity and reliability of the MMSE
was originated when the scale was successful in separating 206 patients with a variety of psychiatric disorders
such as depression, depression and cognitive impairment, and dementia (Folstein, Folstein, & McHugh,
1975).
Blessed Dementia Rating Scale (BDRS): (Morris, Heyman, Mohs, Hughes, Van Belle, Gillenbaum, Mellits, Clark, & the CERAD investigators 1989; Blessed, Tomlinson, & Roth 1968). This scale
characterizes the performance of Activities of Daily Living that are affected by dementia. This form is
completed by the informant and determines the loss of abilities due to mental or physical reasons. The BDRS
scale score ranges from 0-17 [mild dementia (score: 0-5), moderate dementia (score: 6-11), and severe
dementia (score 12-17).]. The informant related whether the subject had no loss, some loss or severe loss of
ability in areas of cognition and everyday activities. The ADLs were scored on the level of assistance the
subject needed on a 3 point scale. For all items the informant noted the need for assistance due to mental or
physical reasons. The BDRS has good validity, good test-retest reliability and internal consistency
(Pena-Casanova, Monllau, Bohm, Aquilar, Sol, Hernandez, & Blesa, 2005).
Dementia Severity Rating Scale (DSRS): (Clark & Ewbank, 1996). This is a 12 item scale that assesses domains that are affected by Alzheimer’s disease. It is a multiple choice questionnaire completed by the
informant. The DSRS total score is obtained from the summed scores across all items. Item 12 response is on
a 10-point likert-type scale that is reflected as a percentage. It assesses the severity of cognitive functional
impairment. The DSRS is high in both reliability and validity. It has ideal characteristics that are valuable in
clinical trials (Clark & Ewbank, 1996).
Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): Developed by Jorm (1994). The short form was used containing 16 questions that deal with the assessment of memory and cognitive
functions compared to 2 years ago. The scores were summed then divided by 16. A score of 3 means that the
subject is rated on average as having “no change” in functioning; a score of 4 means an average of “a bit
worse”; a score of 5 means an average of “much worse”. This form is filled out by the informant. It carries
both high validity and reliability. Jorm reported test-retest reliability for over three days to be 0.96 and 0.75
Mental and Emotional Strain Scale: This is a 6 question scale taken form the Caregiver Health Effects Study and measures caregiver strain. The Mental and Emotional Strain answers were recoded to eliminate
skipped or don’t know responses. The Caregiver Health Effects Study was a secondary study to the
Cardiovascular Health Study, which examined spousal caregivers. The Caregiver Health Effects Study
revealed that only half of the providers reported mental or physical strain associated with caregiving:(Schulz,
Newsom, Mittelmark, Burton, Hirsch & Jackson, 1997; Schulz & Beach, 1999).
Procedure
In order to gain access to the Aging and Demographics Memory Study (ADAMS) datasets, a Health and
Retirement Study Sensitive Health Data Use Agreement form was submitted to the Health and Retirement
Study DUA Review Committee. Once the authentication process was completed, authorization to access the
ADAMS dataset was given.
Results
The stepwise regression revealed the IQCODE to be the highest predictor of caregiver depression.
Variables not entering prediction included the DSRS, BDRS and MMSE. The IQCODE explained 6.3% of
the variance (adjusted R² = .060) in Caregiver’s Depression (F (1,320) = 21.603, p<.001) (See Table 1).
In the block wise regression the first variable entered was the MMSE which assessed the care
recipients’ cognitive status. Lower scores on the MMSE predicted depression in the caregivers. The second
step entered both the BDRS and the DSRS variables which looked at the recipients functioning abilities. The
addition of the ADL and IADL measures did not significantly improve upon prediction. The third step
entered the IQCODE variable which deals with the caregivers’ perception of decline. The fourth and final
step included entering the Mental and Emotional Strain variable. Adding in the perception of the care
recipients decline in abilities (IQCODE) resulted in a significant F change (F (4,254) =6.983, p<.001).
Providing an increment in the prediction of caregiver depression the mental and emotional strain revealed TABLE 1
Stepwise Regression Predicting Caregiver Depression from Cognitive and ADL Data
Step and Predictor B SE B Beta R square change F change
IQCODE .418 .090 .251** .063 21.603**
Note: IQCODE: R²=.063, (adj. R²=.060), F(1,320)=21.603, p<.001 **p<.001
(adjusted R² = .160), a relationship between feeling strained and becoming depressed (F (5,253) =10.830,
p<.001), and also improved the prediction of depression when included along with the MMSE & IQCODE
(See Table 2).
Discussion
The IQCODE results reveal that including a strong relationship with caregiver depression, the
more the caregiver perceives the person declining the more it depresses them. The overwhelming
responsibilities one covers may play a role in their level of depression and anxiety (Ferrara, Langiano, Di
Brango, De Vito, De Ciaoccio, & Bauco, 2008). The severity of Alzheimer’s disease and the burden of
responsibilities are determining factors of a caregiver’s level of depression. This study supports this notion,
but also provides information about the relative impact of various experiences on the caregiver. While lower TABLE 2
Block Wise Regression Demonstrating Incremental Prediction of Caregiver Depression by Cognitive Status, ADLs/IADLs, Perceived Decline, and Mental and Emotional Strain
Step and Predictor B SE B Beta R square change F change
Step 1: Cognitive Status .018 4.582*
MMSE -.011 .005 -.132* Step 2: ADLs/IADLs .001 .159 MMSE -.011 .005 -.128* Blessed .020 .047 .052 DSRS -.009 .016 -.067 Step 3: Caregivers Perception of Decline .080 22.649** MMSE -.011 .005 -.134* Blessed -.020 .046 .050 DSRS -.009 .015 -.067 IQCODE . 483 .102 .284**
Step 4: Mental and
Emotional Strain .077 23.720** MMSE -.009 .005 -.108 Blessed .025 .044 .064 DSRS -.011 .015 -.081 IQCODE .211 .112 .124 ME Strain .168 .035 .321**
Note: Step 3: R²=.099, (adj. R²=.085), F(4,254)=6.983, p<.001. Step 4: R²=.176, (adj. R²=.160), F(5,253)=10.830, p<.001. **p<.001
cognitive functioning of the care recipient predicted depression in the caregiver, the addition of problems in
ADLs did not add to the prediction of depression. The caregivers’ perception of decline notably contributed
to the caregivers’ depression. The reported experience of “strain” on the caregiver also significantly
enhanced prediction. Thus, while low cognitive functioning in a care recipient may negatively impact mood,
the caregivers’ perception of decline in the caregiver, and their self-reported level of strain are also strong
contributors to the degree of depression experienced. In summary, this study has helped to gain insight into
the predictors of caregivers’ depression.
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**Note: This analysis uses Early Release data from the Health and Retirement Study, ADAMS, sponsored by
the National Institute of Aging (grant number NIA U01AG009740) and conducted by the University of
Michigan. These data have not been cleaned and may contain errors that will be corrected in the Final Public
