ORIGINAL ARTICLE

Depression in informal caregivers of persons with dementia Rita F. D’Aoust

PhD, ANP-BC

Associate Professor and Associate Dean, College of Nursing, University of South Florida, Tampa, FL, USA

Glenna Brewster

MS, FNP-BC

Predoctoral Fellow, College of Nursing, University of South Florida, Tampa, FL, USA

Meredeth A. Rowe

PhD, RN

Professor, College of Nursing, University of South Florida, Tampa, FL, USA

Submitted for publication: 14 March 2013 Accepted for publication: 4 October 2013

Correspondence: Rita F. D’Aoust 12901 Bruce B. Downs Blvd MDC22, 33612 Tampa, FL USA Telephone: +813 974 3195 E-mail: [email protected]

D’AOUST R.F., BREWSTER G. & ROWE M.A. (2015) Depression in informal caregivers of persons with dementia. International Journal of Older People Nursing 10, 14–26. doi: 10.1111/opn.12043

Background. Worldwide, there are more than 35 million individuals diagnosed with Alzheimer’s disease. Many of these individuals are cared for at home by unpaid caregivers who often report high levels of depressive symptoms and depression. The majority of studies conducted to predict which caregivers are at risk for depression have examined non-modifiable risk factors. Therefore, it is important to discover modifiable factors that may be associated with risk for depression in caregivers. Objectives. The aims of this research were to identify a set of factors that are modifiable and known to be associated with high levels of depression/depressive symptomology (D/DS) in other populations and to determine whether these factors are predictive of D/ DS after controlling for non-modifiable, demographic, and clinical factors. Design. Secondary data analysis. Methods. Fifty-three participants provided direct care to a person with dementia with night-time activity. Inclusion criteria included not undergoing treatment for sleep disorders; living with the care recipient; and a Mini-Mental Status Exam score > 27. Baseline data collected by questionnaires, sleep diary and actigraphy. Results. In multivariate analyses of the modifiable factors, only high levels of negative affect predicted higher levels of depressive symptomatology. When nonmodifiable factors were included in the model, negative affect and high levels of perceived caregiver burden predicted 52.6% of the variance in depressive symptomology. In secondary analyses, wake after sleep onset misperception was associated with higher depression scores. Conclusions. While negative affect had a moderate effect on depressive symptoms, modifiable factors often associated with depressive symptoms in other studies were not associated with caregiver depression in this study. Possibly caregivers’ overall poor sleep causes a floor effect and masks a potential relationship. Implications for practice. Both caregivers’ affect and perceived burden are strongly related to depressive symptoms, so healthcare practitioners need to frequently assess both so as to provide timely interventions. Key words: affect, Alzheimer’s disease, carers, dementia, depression, sleep

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© 2014 John Wiley & Sons Ltd

Understanding Depression in Caregivers

What does this research add to existing knowledge in gerontology?

• • •

There was a strong relationship between high negative affect and depression/depressive symptoms while low levels of positive affect were not associated with the levels of depressive symptoms. Modifiable factors such as sleep, daytime sleepiness, positive affect, negative affect, caregiving support, and the desire to abandon care were not associated with depressive symptoms in dementia caregivers. Possibly, the overall poor sleep in caregivers caused a floor effect and masked a potential relationship between sleep and depressive symptoms.

What are the implications of this new knowledge for nursing care with older people?

• •

Healthcare providers can teach caregivers to identify possible events that trigger disturbances and develop more effective responses that promote feelings of adequacy and lower levels of negative affect. Healthcare providers must assess depressive symptoms early so as to initiate treatment, manage the depressive symptoms, and potentially improve sleep.

How could the findings be used to influence policy or practice or research or education?

• •

Caregivers with positive wake after sleep onset misperception had higher wake times and depression scores; therefore, caregivers who report poor sleep should be screened for depression. Healthcare professionals and researchers need to further examine ways to increase positive affect and decrease negative affect in caregivers by identifying interventions aimed at daily mood.

Introduction Every 4 seconds, a new case of dementia occurs in the world. In 2010, the Alzheimer’s Disease International reported an estimated 35.6 million people with dementia worldwide. This number is expected to double every 20 years, and by 2050, the prevalence of global Alzheimer’s disease is estimated to reach 115.4 million. The majority of the increase will occur in developing countries rising from 58 to 71% (Wimo & Prince, 2010). © 2014 John Wiley & Sons Ltd

Most individuals with Alzheimer’s disease (AD) are cared for at home. For instance, in the United States, eighty percent of persons with dementia (PWD) receive care at home by more than 15 million unpaid, informal caregivers. These caregivers provide 17.4 billion hours of unpaid care, an estimated value of $210 billion (Zarit et al., 1980; Alzheimer’s Association’s, 2012). Caring for a person with Alzheimer’s disease or other dementias is often demanding and can have serious negative health consequences for the caregivers, depression being one of the most common (Covinsky et al., 2003; Vitaliano et al., 2003; Schulz & Martire, 2004; Epstein-Lubow et al., 2008; Joling et al., 2010, 2012; Schoenmakers et al., 2010). In fact, the incidence of depression in spousal caregivers for persons with dementia has been estimated to be four times higher than in spouses with a cognitively intact partner (Joling et al., 2010). Many studies have shown that informal caregivers are more frequently diagnosed with clinical depression as well as having higher levels of depressive symptoms as compared to non-caregivers.

Review of Literature Depression and high levels of DS have important potential adverse consequences for caregivers, including physiologic changes such as prolonged sympathetic activation, increased platelet activity, cognitive decline, and signs of metabolic syndrome (Aschbacher et al., 2008, 2009; Kohler et al., 2010; von Kanel et al., 2011). These known changes could potentially be associated with the worsening of the caregivers’ health, including higher rates of cardiovascular disease and earlier mortality (Schulz et al., 1995; Schulz & Beach, 1999; Pinquart & Sorensen, 2007). Furthermore, depressed caregivers are more likely to relinquish the caregiver role, often resulting in formal care placement of the care recipient (Joling et al., 2010; Schoenmakers et al., 2010). Non-modifiable factors A number of studies have been conducted to identify predictors and variables associated with high levels of depression and/or depressive symptoms (D/DS) in caregivers. The most common factors that have been studied include gender, age, race/ethnicity, education, relationship to care recipient, precaregiving health status, CG burden, and role strain (Meshefedjian et al., 1998; Martire & Hall, 2002; Covinsky et al., 2003; Gitlin et al., 2003; Takahashi et al., 2005; Joling et al., 2010). These studies often include care recipient factors, such as severity of dementia, behavioural symptoms of dementia, care recipient depression, and need for assistance with activities of daily living as predictors (Zank & Frank, 2002; Covinsky et al., 2003). Many of these 15

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factors lead to higher levels of caregiver burden, which can be difficult to reduce because these care recipient factors are either impossible or difficult to change. In most cases, care recipient factors, in comparison with caregiver factors, have been stronger predictors of caregiver D/DS, particularly with high levels of care recipient behavioural symptoms. Modifiable factors associated with high levels of D/DS Several modifiable factors have also been associated with increases in D/DS in caregivers of PWD. These include sleep, affect, social support, and the desire to relinquish care. Poor sleep is one factor that is strongly associated with D/DS. Poor sleep, defined as high amounts of unwanted wake time after going to bed, is a predictor of future depression, worse depression, and more depression treatment failures (Buysse, 2004; Berk, 2009). In studies focusing on caregivers of PWD, there were consistent relationships between D/DS and sleep (McCurry et al., 2009). Caregivers of PWD report greater problems with sleep than similar-aged non-caregivers, including low sleep efficiency, longer time to fall asleep, and poor self-reported sleep quality (Kochar et al., 2007; McCurry et al., 2007; Beaudreau et al., 2008; Castro & Daltro, 2009). For instance, older, depressed caregivers were 2.5 times more likely to have sleep problems than non-depressed caregivers. Alterations in affect have also been commonly associated with depression. Positive affect and negative affect are two independent dimensions of affect or mood. While positive affect reflects one’s level of excitement, interest, and enthusiasm, negative affect displays one’s level of distress, fear, and relaxation (Watson et al., 1999). There is evidence that caregivers have altered levels of positive affect and negative affect (Lawton et al., 1991; Pinquart & Sorensen, 2004; Mausbach et al., 2008). Research indicates that low levels of positive affect and high levels of negative affect are each highly correlated with high levels of DS, and each affect contributes unique variance to the prediction of clinical depression (Watson et al., 1988a, 1999; Crawford & Henry, 2004). In caregivers of PWD, the findings of one study confirm this relationship with low positive affect and high negative affect predicting 61% of the variance in DS (Mausbach et al., 2011). Caregiver affect is also influenced by the use of antidepressant medications. While studies indicate low levels of antidepressant use both historically and more recently (4%, 8%, respectively) (Clipp & George, 1990; Mausbach et al., 2009), it is hypothesised that this intervention would be associated with lower levels of DS. Social support refers to the various types of assistance that caregivers receive from others. This assistance, either formal or informal, may be emotional, instrumental, or informational in nature and may include respite care (Savage & 16

Bailey, 2004). Increased social support has been linked to greater well-being (Cohen & Wills, 1985; Cohen et al., 1986), and caregivers who have greater support from their spouses and families have lower risk for depression (Thompson et al., 1993; Atienza et al., 2001). In summary, it is vital to understand the multiple factors that influence D/DS in caregivers of PWD. Prior research has focused largely on non-modifiable factors, including demographic and clinical factors, in both the caregiver and care recipient. It is important to understand the influence of modifiable risk factors for D/DS in caregivers of PWD to assist clinicians in appropriately assessing risk and targeting interventions to reduce the development of adverse caregiver health outcomes and subsequent effects on the caregiving role. The goals of this research therefore were first to identify a set of factors that are modifiable (amenable to change) and known to be associated with high levels of D/DS in other populations. These factors include impact of sleep, positive affect, negative affect, caregiver support, and the desire to relinquish care. Secondly, we wanted to determine whether these factors are predictive of D/DS after considering nonmodifiable factors and controlling for demographic and clinical factors commonly associated with depression in caregivers.

Methods Study design The study was conducted using secondary data analysis with data from a study of caregivers of persons with dementia. The parent study was a controlled, clinical trial designed to test the effectiveness of a night-time home monitoring system in improving sleep in caregivers and safety for persons with dementia (Rowe et al., 2008, 2010). The baseline measures of the parent study were used for this analysis. Sleep and affect were measured daily for seven consecutive days, with questionnaires for other variables administered on day 1 of data collection.

Subjects Participants in this (and the original) study were primary, inhome caregivers providing direct care to a person with dementia who had night-time activity. Inclusion criteria for the study sample included: (i) ability to speak and read English; (ii) not being actively treated for sleep disorders; (iii) living with the care recipient; and (iv) a Mini-Mental Status Exam (MMSE) score > 27. Further, the care recipient had to © 2014 John Wiley & Sons Ltd

Understanding Depression in Caregivers

have an MMSE < 23, a medical diagnosis of dementia, and the caregiver reported night-time awakenings. Subjects were initially recruited by placing study notices in caregiver newsletters, the local newspaper, local memory disorder and geriatric clinics, and during presentations at caregiver meetings and support groups. In the parent study, 56 informal caregivers were recruited. Two caregivers who had undergone an initial home visit did not participate, one due to a score of < 27 on the MMSE and the other due to family concerns about participation. One caregiver was not able to complete the sleep diary and was eliminated from analysis for this study at baseline.

Measures Depression The Center for Epidemiologic Studies Depression Scale (CESD) was used in the original study to assess depressive symptoms for caregivers (Radloff, 1977). The CES-D is a 20item self-report measure that asks respondents to rate, on a 4-point scale from 0 (rarely or none of the time) to 3 (most of the time), how often they have had the symptoms during the last week. The summed scores range from 0 to 60, and higher scores represent more depressive symptomology. The CES-D is valid and has high internal consistency and adequate test– retest reliability (Radloff, 1977). The CES-D has also been used to assess prevalence of symptoms in the elderly and has demonstrated sensitivity and specificity with regard to detecting a high level of depressive symptomology in older adults (Callahan et al., 1994; Beekman et al., 1997). The CES-D depression screening instrument is widely reported in the literature to have predictive validity with a clinical diagnosis of depression based on depressive symptomology scores (Penninx et al., 1999). A number of other studies use screening instruments measuring depressive symptomology in lieu of a clinical diagnosis for depression with similar results (Kochar et al., 2007; McCurry et al., 2009). Sleep Caregiver sleep was assessed both objectively and subjectively for seven nights. Actigraphy was the objective measure and consisted of non-invasive monitoring of sleep–wake cycles using wrist activity. The use of actigraphy in the collection of the data has been described in previous literature (Rowe et al., 2008, 2010). The caregivers’ sleep diaries were used to set the bedtime and out-of-bed time on an ActiWatchL by Respironics, Inc., which collects activity on one channel that uses an omnidirectional accelerometer (sensitivity of = 0.01 g-force) and another channel that integrates ambient light levels (MiniMitter Company Incorporated, © 2014 John Wiley & Sons Ltd

2001). Sleep start and sleep end were established by the proprietary Actiware software using standard algorithms (after a 10 minutes period where no more than one epoch is scored as wake and the last 10 minutes period where no more than one epoch was scored as sleep, respectively). A literature review of studies using sleep diaries was conducted, and the authors concluded that sleep diaries are valid and reliable methods for measuring subjective sleep and strongly recommended the inclusion of both subjective and objective measures in evaluation of sleep (Lichstein et al., 1999). For the subjective sleep measures in this study, sleep diaries were used to collect data on bedtime, sleep start, number of awakenings, minutes awake during night, wake time, out-ofbed time and minutes spent napping the previous day, as well as a rating of sleep quality for that night’s sleep (Johns, 1991; Lichstein et al., 1999). These values were then used to create values for total sleep time and wake after sleep onset. The Epworth Sleepiness Scale (ESS) is an 8-item selfadministered scale that was used to measure daytime sleepiness (Johns, 1991). Common daytime activities, such as watching television, were assessed with regard to how likely they were to induce sleep. Each item ranged from 0 (would never doze) to 3 (high chance of dozing) with summed scores ranging from 0 to 24, and higher scores indicate more daytime sleepiness. The ESS has demonstrated adequate validity and reliability (Johns, 1991, 1992). The Cronbach’s a in this study was 0.73. Affect The Positive Affect and Negative Affect Scale (PANAS) is a 10-item self-report survey used to measure two independent dimensions of emotional experience, positive affect and negative affect (Watson et al., 1988b). Five items measured positive mood states (excited, strong, alert, determined, and active), and the other five items measured negative mood states (distressed, scared, irritable, nervous, and jittery). Participants rated the extent to which they experienced each of the 10 mood states upon awakening in the morning using a 5-point scale ranging from 1 (not at all) to 5 (very much). The PANAS was used in this study to measure caregiver mood for each of the 7 days. Summed scores for positive affect and negative affect were created for each of the 7 days, and a mean score was calculated separately for positive affect and negative affect. The Cronbach’s a was 0.96 for the PANAS instrument used in this secondary analysis for this study. Caregiver burden The Zarit Caregiving Burden Interview (CBI) is a commonly used measure to assess perceived stress in research on caregivers of persons with dementia (Zarit et al., 1980, 1985). Validity 17

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and reliability for the shortened 12-item version of CBI used in this study has been reported in the literature (Bedard et al., 2001; Campbell et al., 2011). For the CBI, caregivers selfdescribe aspects of burden on a scale ranging from 0 (never) to 4 (nearly always), with a possible range of 0 to 48. The Cronbach’s a for this study sample was 0.89.

Statistical analysis 20.0 (IBM, Armonk, NY, USA) was used to analyse the data. Descriptive statistics, correlational analyses and regression analyses were used to examine relationships between caregiver characteristics, caregiver resources, caregiving demand including sleep measures, and depressive symptomology.

SPSS

Results The means, standard deviations, and percentages for fixed and modifiable variables and DS used in this study are reported in Table 1. Caregivers were predominantly white, female, and spouses of the care recipients. The ages of the caregivers ranged from 38 to 86 years with the average age being 63. The group tended to have higher levels of education, with all caregivers having at least a high school education, and 30% having a college degree. There was a good range of scores on the CES-D, with 40.7% scoring in the minimal range (0–9). The CES-D mean score, 14.33 (SD = 10.61), approached the cut-off score for significant depressive symptomatology with 31.5% of caregivers scoring over that cut-off score of 16. A small percentage of caregivers (14.8%) reported the use of antidepressant medications, but the CES-D scores did not differ based on reported drug use (t = 0.79, P = 0.43). From actigraphy data, only 8.3% of the caregivers received at least 7 h of sleep, only 25% reported they had less than 30 minutes of WASO, and none of the caregivers were found to have sleep efficiencies greater than 85% SE as recommended by clinical guidelines established by the American Association of Sleep Medicine (Ohayon et al., 2004; Schutte-Rodin et al., 2008). However, caregivers’ subjective measures of sleep (sleep diary) indicated that 29.8% reported > 7 h of sleep, 38.5% were found to have SE > 85%, and 42.3% thought they had < 30 minutes of WASO. Each of these measures indicates that most caregivers did not get recommended levels of uninterrupted sleep, and this poor sleep is reflected in the high daytime sleepiness scores (mean = 8.17) – which is almost twice that of the general population (4.4–4.6). Approximately 25% of caregivers’ approach the score of 10, in which further evaluation of daytime sleepiness is recommended. 18

As in previous studies, caregivers had high levels of negative affect and low levels of positive affect. The caregivers’ mean score for negative affect for the sample (8.17) compares with the 37th percentile for the general population. The caregivers’ average score for positive affect of 13.29 compares with the 26th percentile for the general population. The majority of caregivers reported they did not receive any respite care from a spouse, family member, friend, or paid caregiver (64.8%), and no one received support more frequently than once a week. The support caregivers received was primarily provided by a paid caregiver. About half the sample was not taking actions to pursue out-of-home placement for the care recipient; however, 20.4% initiated one action and 22.2% executed > 1 action. In the bivariate analyses, only one non-modifiable variable, high levels of caregiver burden, was significantly associated with levels of depressive symptomology as depicted in Table 2. High levels of burden were strongly associated with high levels of depressive symptomology. Analyses for depressive symptomology and modifiable variables are shown in Table 3. Only three modifiable variables were significantly correlated with higher depressive symptomology: high levels of subjective WASO, high levels of negative affect and low levels of subjective SQ.

Multivariate analyses To understand the relationship between the predictors and depression/depressive symptomology, the variables that had bivariate correlations that were statistically significant or approached significance (P < 0.10) with depressive symptomology were entered into two separate backward regression models. Model A included only significant modifiable variables, and Model B included all significant fixed and modifiable factors. In Model A (see Table 4), with the predictors for negative affect, subjective SQ and subjective WASO, the value of the R2 at step 1 was 0.29 (F(df = 3,48) = 5.59, P = 0.01). The final step of backward regression contained only negative affect, and that model accounted for 23.7% of the variance associated with levels of depressive symptomology (F(df = 1,49) = 30.51, P < 0.001). Model B included all significant or near significant nonmodifiable and modifiable factors. Only one non-modifiable factor, caregiver burden, and the three modifiable factors from above were entered (see Table 4). The value of R2 for Model B at step 1 was 0.56 (F(df = 4,47) = 15.17, P < .001). At the last step of the model, only caregiver burden and negative affect remained in the model. These two variables accounted for 52.6% of the variance in depressive symptomology (F(df = 2, 49) = 30.35, P < 0.001). © 2014 John Wiley & Sons Ltd

Understanding Depression in Caregivers Table 1 Means and percentage values of study variables Percentage (n)

Variable Fixed factors Gender Female Race or ethnic group White Black Hispanic Age Spousal caregiver Yes Employment Yes Number of meds (poor health) Caregiver burden Modifiable factors Subjective sleep TST SE SOL WASO SQ Objective sleep TST SE SOL WASO Daytime sleepiness Daily mood Negative affect Positive affect Anti-depression medication Other support for Caregiver duties Desire to institutionalise Outcome variable Depressive symptoms

Standard deviation

Mean

Minimum value

Maximum value

79.6 (43) 77.8 (42) 18.5 (10) 3.70 (2) 63.15

12.0

38.00

86.00

51.8 (28) 31.5 (17) 2.48 2.80

2.52 0.80

0 1

10 4.67

380.11 78.06 30.24 45.85 3.03

62.72 11.39 21.31 34.23 0.62

168.33 48.00 5.71 4.71 1.86

480.00 93.00 96.50 136.43 4.43

353.28 72.11 24.30 43.83 8.17

48.79 6 18.50 19.6 4.03

211.90 54.63 2.45 15.53 0

453.37 81.28 86.73 105.36 19

8.17 13.29

2.52 3.49

4.57 5.33

14.71 22.14

1.02

1.68

0

6

14.33

10.61

0

40

17.4 (8) 35.2 (19)

SE, sleep efficiency; SOL, sleep onset latency; SQ, sleep quality; TST, Total sleep time; WASO, wake after sleep onset.

Table 2 Correlations between depressive symptoms and fixed variables 2 1 2 3 4 5 6 7 8

9

Depressive symptoms Gender Age Race or ethnicity Spouse Currently working Education Health status (total number of prescribed caregiver meds) Caregiver burden

0.06

3

4 0.15 0.18 –

5 0.09 0.05 0.54*** –

6 0.09 0.09 0.66*** 0.28 –

7 0.14 0.14 0.36** 0.29** 0.31** –

8 0.13 0.06 0.15 0.09 0.19 0.36*** –

9 0.20 0.20 0.39** 0.41*** 0.22 0.17 0.21 –

0.72*** 0.17 0.11 0.15 0.19 0.05 0.03 0.15

1

*P < 0.10, **P < 0.05, ***P < 0.00. © 2014 John Wiley & Sons Ltd

19

20

DS TST-SD SE-SD SOL-SD WASO-SD SQ-SD TST-A SE-A SOL-A WASO-A NA PA ESS ADM O CG Sup DIS

0.08 –

3

0.04 0.80** –

4 0.02 0.17 0.52** –

5 0.27* 0.31 0.66** 0.26 –

6 0.33* 0.42** 0.44** 0.29 0.27 –

0.24 0.45** 0.17 0.15 0.16 0.22 –

7

8 0.08 0.19 0.34* 0.30 0.20 0.11 0.67** –

9 0.10 0.07 0.11 0.52** 0.04 0.04 0.12 0.50** –

0.02 0.16 0.18 0.04 0.42** 0.01 0.15 0.53** 0.07 –

10 0.58** 0.04 0.06 0.04 0.21 0.37* 0.27 0.29 0.04 0.15 –

11 0.04 0.10 0.28 0.21 0.25 0.02 0.13 0.04 0.18 0.12 0.05 –

12

0.14 0.01 0.03 0.02 0.15 0.16 0.36* 0.34* 0.09 0.06 0.03 0.09 –

13

0.03 0.10 0.05 0.12 0.02 0.02 0.15 0.17 0.07 0.24 0.21 0.12 0.27 –

14

0.15 0.04 0.03 0.25 0.09 0.06 0.22 0.41** 0.36* 0.13 0.17 0.13 0.15 0.16 –

15

0.11 0.20 0.19 0.03 0.2 0.28 0.01 0.01 0.06 0.05 0.24 0.07 0.04 0.02 0.03 1

16

CES-D, depressive symptoms; TST-SD, subjective total sleep time; SE-SD, subjective sleep efficiency; SOL-SD, subjective sleep onset latency; WASO=SD, subjective wake time after sleep onset; SQ-SD, subjective sleep quality ; TST-A, objective total sleep time ; SE-A, objective sleep efficiency; SOL-A, objective sleep onset latency; WASO-SD, objective wake after sleep onset ; NA, negative affect; PA, positive affect; ESS, daytime sleepiness; anti-depress meds, anti-depressant medication ; Other CG support, other caregiver support; DIS, desire to institutionalise. *P < 0.10, **P < 0.05, ***P < 0.001.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

2

Table 3 Associations for depressive symptoms and modifiable variables

R.F. D’Aoust et al.

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Understanding Depression in Caregivers Table 4 Regression models with fixed and modifiable variables

Model A Step 1 NA Subjective Step 2 Subjective NA Step 3 Subjective NA Model B Step 1 NA CBI Subjective Step 2 Subjective NA CBI Step 3 Subjective NA CBI

Unstandardized coefficients

Standardized coefficients

B

b

Std. error

t

P

1.82 0.06

0.54 0.04

0.45 0.19

3.37 1.49

0.001 0.14

SQ

0.58 1.87

2.30 0.50

0.04 0.46

0.25 3.74

0.80 0.00

WASO

0.06 2.04

0.04 0.50

0.20 0.50

1.64 4.11

0.11 0.00

0.83 8.18 0.03

0.47 1.51 0.03

0.21 0.59 0.09

1.79 5.41 0.87

0.08 0.00 0.39

SQ

0.61 0.88 8.18

1.82 0.44 1.50

0.04 0.22 0.59

0.34 2.02 5.46

0.74 0.05 0.00

WASO

0.03 0.93 8.46

0.03 0.43 1.47

0.10 0.23 0.61

1.00 2.15 5.75

0.32 0.04 0.00

WASO

WASO

Dependent Variable: CES-D, depressive symptomology. NA, Negative affect; CBI, caregiver burden; Subjective WASO, subjective wake after sleep onset; Subjective SQ, subjective sleep quality. Regression Model A: Modifiable Variables Coefficients: Step 1 R2 = 0.29 (P = 0.001); Step 2 R2 D = 0.001, P = 0.80; Step 3 R2 D = 0.04, P = 0.11. Regression Model B: Fixed and Modifiable Variables Coefficients: Step 1 R2 = 0.56 (P = 0.000); Step 2 R2 D = 0.001 (P = 0.74); Step 3 R2 D = 0.01 (P = 0.32).

Discussion Affect In this study, there were both a very high level of negative affect and a strong relationship between negative affect and depression/depressive symptomology. Mood is a dynamic affective state that reflects an individual’s emotional state and ability to respond to a continuously changing environment. The challenges and difficulties in caregiving role, such as the high mental and physical demands of providing care, could be a significant source of the high levels of negative affect. The need for constant vigilance has also been identified as a major caregiving challenge and may lead to high levels of negative affect (Mahoney, 2003). Because dementia results in continual deterioration and increasing caregiving demand, caregiver actions may not seem to make a difference and be associated with high levels of negative affect. Each situation © 2014 John Wiley & Sons Ltd

or demand contributes to a feeling of adequacy or inadequacy in dealing with the situation and thus changes daily depending on the demand. The nature of escalating demands coupled with inadequacy with a satisfying outcome contributes to levels of distress, fear, scorn, and other dimensions of negative affect (Watson et al., 1999). Cognitive strategies have been shown to selectively improve negative affect (Mausbach et al., 2009). Teaching caregivers to monitor problems, identify possible events that trigger disturbances, and develop more effective responses are cognitive strategies that promote feelings of adequacy and lower levels of negative affect (McCurry et al., 2005). Providing information, role playing, problemsolving, and other skills training provide caregivers with actions to respond to multiple situations at hand that occur with dementia care. Increasing the arsenal of actions promotes feelings of adequacy and lower levels of negative affect. 21

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Others suggest that a tripartite model of low levels of positive affect and high levels of negative affect contribute to depression/depressive symptomology (Clark & Watson, 1991; Watson et al., 1995a,b; Mausbach et al., 2009). However, in this study, low levels of positive affect were not associated with the levels of depressive symptomology. The lack of finding may be associated with the sample’s very low levels of positive affect and the restricted variance of positive affect scores. In the tripartite model, depressive symptomology appear to consist of both positive and negative dimensions, and it is important to consider the role of both negative affect and positive affect. While cognitive strategies are effective in decreasing negative affect, behavioural activation activities are associated with increasing positive affect levels. The independent role of positive affect is important for clinicians to consider because positive affect may serve as a buffer against the adverse effects of stress. The effect of high levels of negative affect frequently found with chronic caregiver stress and burden can be mitigated by improving levels of positive affect (Mausbach et al., 2011). Strategies that promote positive affective experiences in the midst of chronic, stressful conditions associated with caregiving burden may buffer the feelings of helplessness, loss of control, and feelings of inadequacy. Strategies such as behavioural activation through the participation in social and physical activities, positive reappraisal (reframing a situation in a positive light), and appraised situational meaning (the evaluation of personal significance in a stressful situation) are useful strategies for clinicians to employ (Folkman & Moskowitz, 2000; Mausbach et al., 2011).

Sleep The relationship between sleep and depression in this sample of caregivers of persons with dementia differs from the general population where sleep and depression are significantly related (Perlis et al., 2006; Van Dam & Earleywine, 2011). The lack of findings between sleep and depressive symptomology may be attributed to the fact that most caregivers in this study had sleep that was less than optimal, with both low levels of total sleep time and high levels of wake time on both objective and subjective sleep measures. Although it is common for other investigators to find low levels of sleep in caregivers of a person with dementia, it is possible that these levels were lower in this study because all care recipients had to have evidence of

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night-time activity to participate in the parent study. However, this behaviour has not been strongly associated with worsened caregiver sleep when the behaviour occurs over time (Rowe et al., 2010). The only sleep variable that was significantly related to depression was subjective WASO, but that relationship lost significance when burden was entered into the model. It is possible that one’s rating of sleep is influenced by depressed mood. To understand the relationship between depression and subjective WASO, but not objective WASO, an additional analysis was run based on WASO misperception. WASO misperception was calculated by subtracting objective WASO from subjective WASO. Positive numbers in this variable indicated that subjective WASO was higher than objective WASO, with negative numbers meaning objective WASO was higher. Examining the graphs, it is evident that the relationship between depressive symptomology and subjective WASO is different between the two groups. For those with positive WASO misperception, there is a moderate, positive correlation between higher wake times and higher depressed/depressive symptomology scores (see Fig. 1: Graph 1). No relationship exists for those with negative WASO misperception (see Fig. 1: Graph 2). The implication of this finding is that the depressed caregivers report greater wake times than are supported with objective evidence, and treatments to improve sleep may not have the perceived benefit without also treating the depression. Also, treating the depression may reduce the perception of excessive wake time during the night. A finding in this study that was consistent with other studies was that caregivers with high levels of burden are also prone to high levels of depressive symptomology (Covinsky et al., 2003; McCurry et al., 2007; EpsteinLubow et al., 2008). Caregiving demands are determined by the care recipient’s condition and needs, and thus, caregivers have little control over those demands. Although a significant factor in caregiver depression, caregiver burden scores for care provided in the home are relatively stable over time (Berger et al., 2005; Epstein-Lubow et al., 2008; Campbell et al., 2011). Thus, caregiving burden may not be the best target of an intervention to improve depression. Rather, interventions to improve daily mood may provide nurses and other clinicians a better strategy to impact depressive symptomology. Cognitive and behavioural training programmes that focus on depression management and behaviour management provide caregivers with the knowledge and skills to understand and manage daily stressors. Nurses can provide caregivers with this knowledge or refer them to a support group.

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Understanding Depression in Caregivers

Graph 1: Positive WASO misperception

Graph 2: Negative WASO misperception

Figure 1 Relationship between WASO misperception and depressive symptomology. Graph 1: Positive WASO misperception. Graph 2: Negative WASO misperception.

A limitation of this study is the cross-section design and the fact that the parent study recruited caregivers with concerns about care recipients with night-time activity and thus may have had higher levels of burden. One other consideration is that the instruments used for negative mood, caregiver burden, and depressive symptomology are all tapping the same construct. A study by Terracciano et al. (2003) conducted a confirmatory factor analysis and determined the independence of positive affect, negative affect, depressive symptomology (as measured by CES-D), and anxiety. Although anxiety and depression share common features of distress as measured by low levels of positive affect and high levels of negative affect, the constructs differ substantially and were found to be independent of measures for depression and anxiety.

Conclusion Few modifiable factors were associated with D/DS, with caregiver burden, a non-modifiable factor, having the strongest relationship. An important modifiable factor that was associated with both caregiver burden and depression/ depressive symptomology was negative affect. Psychoeducational activities that address negative affect associated with caregiving stress, such as helplessness and blaming oneself, can assist caregivers in developing skills to offset and manage negative emotions (Gallagher-Thompson & Coon, 2007; Mausbach et al., 2009). © 2014 John Wiley & Sons Ltd

Implications for practice  Caregivers should be evaluated regularly and formally for depressive symptomology. Identifying targets that are amenable to intervention is difficult in this population, with only negative affect being significantly related to depression. Interventions to reduce negative mood should be developed for caregivers of persons with dementia, particularly for caregivers with high levels of depressive symptomology.  Healthcare practitioners need to frequently assess caregivers’ affect and perceived burden as these are strongly related to depressive symptoms. When at-risk individuals are identified, they must provide or suggest interventions, such as cognitive strategies, which can potentially reduce the development of depressive symptomatology.

Contributions Study design: RD, MR; data collection and analysis: RD, GB, MR and manuscript preparation: RD, GB, MR.

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