gallagher, s., phillips, a. c., oliver, c. and carroll,...
TRANSCRIPT
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Predictors of psychological morbidity in parents of
children with intellectual disability.
Gallagher, S., Phillips, A. C., Oliver, C. and Carroll, D.
Cerebra Centre for Neurodevelopmental Disorders,
School of Psychology,
University of Birmingham
Please use this reference when citing this work:
Gallagher, S., Phillips, A. C., Oliver, C. and Carroll, D. (2008). Predictors of
psychological morbidity in parents of children with intellectual disability. Journal of
Pediatric Psychology, 33, 1129-1136. (DOI: 10.1093/jpepsy/jsn040)
The Cerebra Centre for Neurodevelopmental Disorders, School of Psychology, University of Birmingham, Edgbaston, Birmingham, B15 2TT Website: www.cndd.Bham.ac.uk E-mail: [email protected]
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Abstract
Objective: This study investigated symptoms of depression and anxiety and their
origins in parents caring for intellectually disabled children relative to parents of
typically developing children.
Design: A cross-sectional case control study.
Methods: Thirty two parents of children with intellectual disabilities and twenty nine
parents of typically developing children completed measures of anxiety and
depression, social support , child problem behaviours, sleep quality and caregiver
burden.
Results: The parents of children with intellectual disabilities registered much higher
depression and anxiety scores on the Hospital Anxiety and Depression Scale and the
majority met the established criteria for possible clinical depression and/or anxiety. Of
the putative mediators measured, the strongest and most consistent predictor of group
differences in distress, as well as individual variations in distress within the group of
parents with intellectually disabled children, was caregiver burden. Analyses of its
component dimensions indicated that the negative psychosocial consequences of
caregiving were particularly predictive of depression, whereas guilt was the main
associate of anxiety.
Conclusions: Symptoms of depression and anxiety are highly prevalent in parents of
children with intellectual disabilities and different dimensions of caregiver burden
predicted depression and anxiety. This suggests that, in developing interventions for
this population, attention should be paid to the way in which parental distress presents
itself as depression, anxiety, or both, in the individual caregiver.
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Key words: Anxiety, caregiving, case control study, depression, parents of intellectual
disabled children
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Introduction
Parents of intellectually disabled children frequently report symptoms of
depression and anxiety (Dunn, Burbine, Bowers, & Tantleff-Dunn, 2001; Eisenhower,
Baker, & Blacher, 2005; Floyd & Gallagher, 1997; Hastings & Brown, 2002; Hastings
et al., 2005a; Hastings et al., 2005b; Piven & Palmer, 1999; Sharpley, Bitsika, &
Efremidis, 1997; Yirmiya & Shaked, 2005). In one UK study, for example, 59% of
parents caring for a child with autism had scores on the General Health Questionnaire
indicative of psychiatric caseness (Bromely, Hare, Davison, & Emerson, 2004). The
cost of such psychological morbidity to the immediate family can be enormous. Poor
parental mental health has been shown to have deleterious consequences for parenting
role, offspring wellbeing, and marital relationships (Dyson, Edgar, & Crnic, 1989;
Early Child Care Research Network, 1999; Fisman & Wolf, 1991; Kahn, Brant, &
Whitaker, 2004; Pilowsky, Wickramaratne, Nomura, & Weissman, 2006). Distressed
parents are more likely to separate and divorce (Pilowsky et al., 2006).
A number of factors have been considered to contribute to the high levels of
psychological morbidity in parents of intellectually disabled children. Two key
factors: the adequacy of social support and the extent of the child’s problem
behaviours have been argued to account for much of the distress observed. Social
support has long been regarded to mitigate distress (Bailey, Wolfe, & Wolfe, 1994;
Dunn et al., 2001) and considerable research has been directed at its role in parents
with an intellectually disabled child. Social support has generally been found to be
inversely related to depression and anxiety in such parents (e.g. Gray and Holden,
1992; Hare, Pratt, Burton, Bromely & Emerson, 2004; McCallion, Janicki, &
Kolomer, 2004; Weiss, 2002). The child's behavioural problems appear to be a major
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source of psychological distress in parents of children with intellectual disabilities
(Baker et al., 2003; Blacher & McIntrye, 2006; Floyd & Gallagher, 1997; Maes,
Broekman, Dosen, & Nauts, 2003). Higher scores on the Aberrant Behaviour
Checklist (Aman, Richmond, Stewart, Bell, & Kissel, 1987) subscales (e.g. lethargy,
stereotypical behaviour, and hyperactivity) was associated with greater distress in
these parents (Stores, Stores, Fellows, & Buckley, 1998). Further, the more
challenging the behaviours that a child exhibits, the greater the recourse to mental
health services by parents (Floyd & Gallagher, 1997).
Sleep quality and caregiver burden have been identified as significant predictors of
psychological distress in other caregivers (e.g. caregivers for Alzheimer’s sufferers,
and people with schizophrenia, and physically disabled children), but have rarely been
examined in the context of parents caring for intellectually disabled children.
However, one concern for parents of children with Downs syndrome was that they
were not getting enough sleep (Hedov, Anneren, & Wikblad, 2002). Sleep quality is
an important aspect of well-being and is strongly related to overall quality of life
(Zammit, Weiner, Damato, Sillup, & McMillan, 1999), secretion of the stress
hormone, cortisol (Spiegel, Leproult, & Van Cauter, 1999), and also to the increased
prevalence of depression and anxiety in various caregiver groups (Brummett et al.,
2006 ; Flaskerud, Carter & Lee, 2000; McCurry, Logsdon, Teri, & Vitiello, 2007;
Wilcox & King, 1999 ). For example, parents caring for a child with a physical
disability (cystic fibrosis and ventilator dependency) were characterized by both poor
sleep quality and depression (Meltzer & Mindell, 2006).
Another source of psychological distress in those caring for demanding others is
perceived caregiver burden (Clyburn, Stones, Hadjistavropoulos, & Tuokko, 2000;
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Maes et al., 2003; Wade, Taylor, Drotar, Stancin, & Yeates, 1998). Perceived burden
includes embarrassment, guilt, overload, feelings of entrapment, resentment, isolation
from society, and loss of control (Zarit, Reever, & Bach-Peterson, 1980). In parents of
children with intellectual disabilities, curtailed employment opportunities, a likely
consequence of burden, were associated with feelings of isolation, lack of fulfillment,
and low self-esteem (Shearn & Todd, 2000). Further, a higher caregiver burden in
parents with intellectually disabilities has been related to a greater need by parents to
use external health services (Maes et al., 2003). However, the role of caregiver burden
in the high level of depression and anxiety symptoms reported by parents caring for
intellectually disabled children has yet to be examined.
The present study aimed to confirm the high levels of psychological morbidity in
parents of intellectually disabled children and explore a diverse range of likely sources
of depression and anxiety using a case control design. The role of functional social
support, child behaviour problems, sleep quality, and caregiver burden were examined.
It was hypothesized: first, that parents’ of children with intellectual disabilities would
report much higher levels of both depression and anxiety than parents of typically
developing children; and second, that poorer social support and sleep quality, more
problematic offspring behaviour, and higher perceived caregiver burdens would be
associated with greater psychological morbidity.
Methods
Participants
Participants were 32 parents of children with intellectual disabilities and 29 parents
of typically developing children. Cases, i.e. parents of intellectual disabled children,
were recruited from syndrome specific family support groups, via invitation letters
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distributed by their respective associations and by advertising on syndrome newsletters
and by word of mouth. Inclusion criteria for these parents were: caring for at least
one child with Downs, Autism, Cornelia de Lange, or Smith-Magenis syndromes; the
intellectually disabled child had to be aged between 3 and 19 years and cared for at
home during the school term. The majority of parents reported caring for a child with
Autism (66%); the remainder were parents of a child with Downs syndrome (22%) and
children with other syndromes (e.g. Cornelia de Lange) (12%). Controls, i.e. parents
of typically developing children, were recruited via local schools, media campaigns
and advertisements placed within University newspapers. The same age of child and
domicile inclusion criteria applied. Attempts were made to match the groups as
closely as possible on age, sex, socioeconomic position, ethnicity, and marital status
(See Table 1).
Measures
Depression and anxiety
Parental psychological morbidity was measured using the Hospital Anxiety and
Depression Scale (HADS) (Zigmond & Snaith, 1983), a well-recognised and respected
assessment tool. The scale contains 14 four-point items, from 0 (not present) to 3
(considerable), with seven assessing largely the anhedonic rather the somatic aspects
of depression (e.g., ‘I have lost interest in my appearance’) and seven assessing
anxiety (e.g., ‘I feel tense or wound up’). The item scores are added, giving sub-scale
scores for depression and anxiety from zero to 21. The HADS has good concurrent
validity (Bramley, Easton, Morley, & Snaith, 1988; Herrmann, 1997), performs well as
a psychiatric screening device (Bjelland, Dahl, Haug, & Neckelmann, 2002;
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Herrmann, 1997), and boasts good psychometric properties; for example, a Cronbach’s
α, an index of internal reliability, of .90 for the depression items and .93 for the anxiety
items has been reported (Moorey et al., 1991) with test-retest reliability coefficients as
high as .85 for depression and .84 for anxiety (Herrmann, 1997). For the present
sample, Cronbach’s α was .86 for both the depression and the anxiety subscales.
Social support
Social support was assessed using the 12-item Support Functions Scale (Dunst,
Trivette, & Deal, 1988). Parents rate each source of support available to them
including practical (e.g. ‘someone to help take care of my child’) and emotional (e.g.
‘someone to talk to about things that worry me’) support on a 5-point Likert scale
ranging from 1, never, to 5, quite often. This scale has been shown to be reliable
(Cronbach’s α =.86) and is used extensively in intellectual disability research (e.g.
White & Hastings, 2004). A high internal consistency (Cronbach’s α =.89) was also
evident for the present sample.
Child’s problem behaviour
The 25-item Strengths and Difficulties Questionnaire (Goodman, 1997), was used
to screen for child behaviour problems. The scale has five subscales, with one
assessing prosocial behaviour (e.g. ‘kind to younger children’) and four assessing
problems behaviours; emotional symptoms (e.g. ‘often unhappy, downhearted or
tearful’), conduct disorder (e.g. ‘often argumentative with adults’), hyperactivity (e.g.
easily distracted, concentration wonders’), and peer relationships (e.g. rather solitary,
tends to play alone’). Parents are asked to rate whether a behaviour is true (1),
somewhat true (0) or certainly true (2) of their child with higher scores indicating more
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problem behaviours. Some items are reversed scored (e.g. generally obedient, usually
does what adults request) so that a true (2) and certainly true (0). The scale has been
shown to be reliable (Cronbach’s alpha = .76) and effective at identifying behavioural
problems in children (Goodman & Scott, 1999). Further, it has been used extensively
in research with intellectually disabled children (Beck, Hastings, Daley & Stephenson,
2004; Hastings, Daley, Burns, & Beck, 2006). For the purposes of our analyses only
the problem behaviour total score was used and a satisfactory Cronbach's alpha was
obtained in the present sample α =.88.
Sleep quality
The Pittsburgh Sleep Quality Index (Buysse, Reynolds, Monk, Berman, & Kupfer,
1989) is a 19-item self-report questionnaire that assesses sleep quality and disturbance.
This index encompasses seven dimensions of sleep: subjective sleep quality, sleep
latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping
medications, and daytime dysfunction. Scores on items range from 0 (no difficulty) in
a particular dimension to 3 (severe difficulty). For some items the 0 (not during the
past month) to 3 (three or more times a week) scale captures frequency. Examples of
items include ‘During the past year, how would you rate your sleeping quality
overall?’ and ‘During the past year, how often have you had trouble staying awake
while driving, eating meals, or engaging in social activity?’. By summing component
scores, a total sleep quality score is obtained that ranges from 0 (good sleep quality) to
21 (poor sleep quality). This index has excellent has been shown to distinguished
between ‘good sleepers’, ‘poor sleepers’ and ‘sleeping disorder patients’ over an 18-
month period (Buysse et al., 1989). The sum of scores of the seven dimensions yields
one global score. The total scale has acceptable internal consistency (Cronbach’s α =
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.83) and good test-retest reliability (r = .85) (Buysse et al., 1989). In the present study
Cronbach’s α for the total scale was .86. The scale has also recently been used to
assess sleep quality in caregiver research (Brummett et al., 2006) including studies of
parents of children with physical disabilities (Wright, Tancredi, Yundt, & Larin,
2006).
Caregiver burden
As a measure of parental caregiver burden, an adapted version of the 22-item
Caregiver Burden Index was used (Zarit, Todd, Zarit, 1986). This index was designed
to assess the stresses experienced by family caregivers of elderly and disabled persons.
It can be administered as interview or questionnaire; we opted for the latter approach.
Questions were amended replacing ‘your relative’ with ‘your child’. Examples of
items include ‘Do you feel that because of the time you spend with your child that you
don’t have enough time for yourself?’, ‘Are you afraid what the future holds for your
child?’, and ‘Overall, how burdened do you feel in caring for your child?’. Responses
range from never (0) to nearly always (4). It has been used extensively in caregiver
research (Ukpong, 2006; Vedhara et al., 2002). High internal consistency (Cronbach’s
α = .94) was evident for the present sample.
Procedure
From 101 contacts, 61 parents were recruited to the study and attended a session at
the University where they provided informed consent. The purposes of the study were
explained in detail and participants were given a pack of psychosocial questionnaires
to complete. They had the option of completing the questionnaires on site or at home,
returning in a prepaid envelope. The study was approved by the relevant Research
Ethics Committees.
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Statistical analyses
Initial analyses of group differences were by Chi-square and univariate ANOVA;
in the latter, η2
is reported as a measure of effect size. Subsequent, analyses were by
regression, mainly testing hierarchical models. Linear regression was applied with
continuous HADS depression and anxiety scores, and logistic regression was used
when possible pathology was determined, yielding binary variables, using established
cut-off values. For analysis involving the whole sample, parental group was always
entered at step 1 as a dummy variable. Regression analyses were also applied within
parental groups. Slight variations in degrees of freedom reflect occasional missing
data for some variables.
Results
Descriptive characteristics of parental groups
Since the parents of children with Down’s syndrome did not differ from the other
cases in terms of the outcome variables, parents of intellectually disabled children
were treated as a uniform case group. The socio-demographic and summary childcare
characteristics of the two parental groups are presented in Table 1. It is evident that
the groups are reasonably well matched on most variables. There are two exceptions;
parents of intellectually disabled children were slightly older on average and were less
likely to be currently employed outside the home.
[Insert Table 1 about here]
Group differences in depression and anxiety
Parents caring for intellectually disabled children had much higher levels of
depressive symptomatology than parents of typically developing children, F(1, 59) =
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41.64, p < .001, η2
= .414. They also had much higher anxiety scores, F(1, 59) =
43.12, p < .001, η2
= .422. A cut-off of ≥ 8 on the depression subscale of the HADS
was used as an indicator of possible pathology (Zigmond & Snaith, 1983). Parents of
intellectually disabled children were much more likely to reach this criterion than
parents of typically developing children χ2
(1) = 18.06, p < .001. The same was true
using the same recommended cut-off for anxiety χ2
(1) = 23.22, p < .001. Table 2
presents the summary data.
[Insert Table 2 about here]
Group differences in social support, sleep quality, child problem and prosocial
behaviours, and caregiver burden
There were significant group differences for four all of these variables. Parents of
intellectually disabled children reported poorer functional social support, F(1, 59) =
6.53, p = .01, η2
= .100, and sleep quality, F(1, 59) = 24.46, p <.001, η2
= .293, greater
child behaviour problems, F(1, 57) = 85.00, p < .001, η2
= .599, and higher caregiver
burden, F(1, 57) = 40.93, p <.001, η2
= .418. The descriptive statistics are presented
in Table 3.
[Insert Table 3 about here]
Contribution of potential mediator variables to group differences in depression and
anxiety
In hierarchical linear regression analysis, in which parental group was entered at
step 1 and the potential mediators individually at step 2, child behaviour problems, β =
.42, t = 2.28, p =.007, ∆R2 = .07, social support, β = -.26, t = 2.59, p = .01, ∆R
2 = .06,
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sleep quality, β = .44, t = 4.17, p <.001, ∆R2 = .14, and caregiving burden β = .53, t =
4.58, p <.001, ∆R2 = .17 were significant predictors of depressive symptomatology. In
these analyses, β for parental group was attenuated from .64 at step 1 to .56, .41, .32
and .31 at step 2, respectively. Accordingly, we tested for mediation in each case
using the Goodman test (Goodman, 1960). In the case of child problem behaviours,
sleep quality and caregiver burden, there was evidence of mediation, z = 2.65, p =.007,
z = 3.23, p =.001, and z = 3.65, p <.001. Thus, it would seem that child behaviour
problems, sleep quality and caregiver burden were not only associated with depression
independently of parental group in these models, but they accounted, at least in part,
for case/control group differences in depression. The outcome of the mediation
analysis is presented in Figure 1.
A further hierarchical regression analysis was undertaken, in which at step 2, social
support, child behaviour problems, sleep quality and caregiver burden were entered.
In this analysis, the effect of parental group was no longer significant, β = .16, p = .25.
However, both social support, β = -.24, p = .009, sleep quality, β = .23, p = .04, and
caregiver burden, β = .48, p = .001 emerged as significant predictors of depressive
symptomatology. In a final regression model, parental group was again entered at step
1. Age and work outside the home were entered at step 2 since they differentiated
groups, and social support, child behaviour problems, sleep quality and caregiver
burden entered at step 3. Again, only social support, β = -.19, p = .03, and caregiver
burden, β = .29, p = .04 were associated with depressive symptomatology; there was
no influence of parental group, β = .10, p = .44.
Similar analyses were undertaken with anxiety score as the dependent variable. In
these analyses, problem behaviours, β = .35, t = 2.28, p = .02, ∆R2 = .05, sleep quality,
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β = .38, t = 3.51, p = .001, ∆R2 = .10, and caregiver burden, β = .60, t = 5.77, p <.001,
∆R2 = .22, emerged as predicators of anxiety. In these analyses, β for parental group
was attenuated from .66 at step 1 to .40, .45 and .29 at step 2, respectively.
Mediation analysis confirmed that child behaviour problems, z = 2.23, p = .02, sleep
quality, z = 3.23, p = .001, and caregiver burden, z = 4.15, p <.001, were candidate
mediators, at least in part, of the association between parental group and anxiety score.
The mediation analysis is presented in Figure 2. In the model in which both child
behaviour problems, sleep quality and caregiver burden were entered after parental
group, only caregiver burden emerged as a significant predictor of anxiety, β = .52, p
<.001. The same was true of the analysis that included age and work outside the
home, β = .51, p = .001.
[Insert Figures 1 and 2 about here]
Sensitivity analysis using the HADS cut-off scores for possible pathology
In logistic regression models with parental group entered at step 1 and the potential
mediators as step 2, a broadly analogous picture emerged. Child behaviour problems,
OR = 1.16, 95% CI = 1.017 – 1.32, p = .02, sleep quality, OR = 1.50, 95% CI = 1.10 –
2.05, p = .01, and caregiver burden OR = 1.17, 95% CI = 1.06 – 1.28, p = .001, proved
to be significant predictors of possible depression. In the sleep model, parental group
remained a significant predictor of possible depressive pathology, OR = 10.36, 95% CI
= 1.81 – 59.21, p = .009, but not for models on child behaviour problems, OR = 4.43,
95% CI = 5.41 –32.28, p = .16, and burden, OR = 4.59, 95% CI = 0.65 – 32.47, p =
.12. In the analysis in which child behaviour problems, sleep quality and caregiver
burden were entered simultaneously, only the latter was associated with depression,
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OR = 1.16, 95% CI = 1.04 – 1.31, p = .01. In this model, parental group did not
significantly predict depression, OR = 4.62, 95% CI = 0.44 – 48.14, p = .20. The same
outcomes were apparent with analyses of anxiety; child behaviours, OR = 1.17, 95%
CI = 1.02 – 1.33, p = .02, sleep quality, OR = 1.41, 95% CI = 1.05 – 1.90, p = .02, and
burden, OR = 1.18, 95% CI = 1.06 – 1.32, p = .003, were associated with possible
pathology. Again, there was no effect of parental group on anxiety in these analyses.
Within group analyses
Linear regression analyses with each of the potential mediators entered separately
as independent variables revealed no significant associations between social support,
child behaviour problems, sleep quality, and caregiver burden and depressive
symptomatology in the control group. However, for parents of intellectually disabled
children, child behaviour problems, β = .34, t = 2.08, p = .04, R2 = 13.3, social support,
β = -.40, t = 2.39, p = .02, R2 = .16, sleep quality, β = .56, t = 3.69, p = .001, R
2 = .31,
and caregiver burden, β = .64, t = 4.34, p <.001, R2 = .41 predicted depression. In a
model, in which all three of these variables were entered simultaneously both social
support, β = -.34, p = .02, and caregiver burden, β = .53, p = .009, were significant
predicators of depressive symptomatology. This model accounted for 56% of the
variance in HADS depression scores within the parents of intellectual disabled
children.
In parallel analyses, only caregiver burden within the control group was associated
with anxiety scores, β = .55, t = 3.16, p = .004, R2 = .30. Within the case group, both
sleep quality, β = .50, t = 3.13, p = .004, R2 = .25, and caregiver burden, β = .66, t =
4.65, p <.001, R2 = .44, predicted anxiety levels. In a model in which sleep quality and
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caregiver burden were both entered, only the latter emerged as a significant predictor,
β = .57, t = 3.15, p = .004; this model accounted for 45% of the variance in anxiety
score among parents caring for a child with an intellectual disability.
In analyses using the criterion ≥ 8 for possible pathology, it was burden which
again emerged as the single predictor of depression, OR = 1.33, 95% CI = 1.04 – 1.69,
and anxiety, OR = 1.15, 95% CI = 1.00 – 1.32.
Caregiver burden
Previous principal component analysis of the caregiver burden index has
uncovered three dimensions of burden: negative social and personal consequences,
psychological burden, and guilt (Ankri, Andrieu, Beaufils, Grand, & Henrard, 2005).
Examples of items loading on these factors are ‘Do you feel that your child currently
affects your relationship with other family and friends in a negative way?’, ‘Do you
feel strained when you are around your child?’, ‘Do you feel you could do a better job
in caring for your child?’, respectively. In regression analyses, entering parental
groups at step 1, and scores on three burden dimensions at step 2, negative social and
personal consequences was a significant predictor of depressive symptomatology, β =
.34, p = .03. Neither of the other two dimensions were significantly associated with
depression score. In contrast, the same analysis applied to anxiety sores revealed that
guilt was the only caregiver burden dimension to significantly predict anxiety levels, β
= .28, p = .02.
Discussion
The present study confirmed that parents caring for a child with an intellectual
disability report substantial symptoms of depression and anxiety (Dunn et al 2001;
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Eisenhower et al., 2005; Glidden & Schoolcraft, 2003; Sharpley et al., 1997; Weiss,
2002; Yirmiya & Shaked, 2005). Almost two thirds of the parents of intellectually
disabled children in the current study met the conventional criterion for possible
depression, and three quarters for possible anxiety. Similar levels of caseness for
depression on the HADS were observed in an earlier UK study, although lower
estimates of anxiety were reported (White & Hastings, 2004). What is clear from our
data and the results of other studies (Carroll, Phillips, Hunt, & Der, 2007; Herrmann,
1997) is that depression and anxiety are co-morbid conditions; in the present study
symptoms of depression and anxiety were highly correlated among the parents of
intellectually disabled children (r = .64). Very few of the parents of typically
developing children met the criteria for possible pathology. The depression and
anxiety scores for these parents were comparable to those found in recent non-clinical
population studies in the UK (Carroll et al., 2007; Crawford, Henry, Crombie, &
Taylor, 2001). Further, whereas none of the control parents met the criteria (HADS
cutoff > 11) for definite depression or anxiety, a third and a half, respectively, of the
parents caring for an intellectually disabled child did. In spite of this, none of these
parents reported taking anti-depressives and only one was using anxiolytics. Other
under-treated at risk populations have been identified previously (Lane, Carroll, Ring,
Beevers, & Lip, 2001).
In terms of the potential pathways to distress, cases and controls differed on all
four putative mediators. Parents of children with intellectual disabilities reported
poorer functional social support and more problematic child repetitive behaviours,
outcomes that resonate with the results of previous research (Dunn et al., 2001;
Eisenhower et al., 2005; Gray & Holden, 1992; Stores et al., 1998; Weiss, 2002;White
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& Hastings, 2004). In the present study, they also reported poorer sleep quality and a
much higher caregiver burden compared to controls. Although, not previously studied
in this context, low sleep quality and demanding caregiver burden has been found for
caregivers of children of physical disabilities, Alzheimer and multiple sclerosis
sufferers, and cancer patients. (Meltzer & Mindell, 2006; Vedhara et al., 2002;Wilcox
& King, 1999; Wright et al., 2006). However, in linear regression analyses, with
parental group entered as a dummy variable, social support, sleep quality, and
caregiver burden emerged as significant predictors of depression. Tests of mediation
identified child problem behaviours, sleep quality and caregiver burden as candidate
mediators. The same mediators emerged from analyses of anxiety scores. In parallel
logistic regression analyses, with possible psychopathology status as the outcome,
child behaviour problems, sleep quality and caregiver burden again proved to be key
predictors of both depression and anxiety.
Analyses within the group of parents caring for intellectually disabled children
implicated much the same variables in depression and anxiety. Sleep quality and
caregiver burden were associated with depression and anxiety scores; additionally,
social support was related to depression score. In analyses of possible pathological
status, however, only caregiver burden predicted whether or not these parents were
depressed or anxious. As expected, child problem behaviours were associated with
depression and anxiety parents of children with intellectual disabilities (Blacher &
McIntyre, 2006; Floyd & Gallagher, 1997; Hastings et al., 2005a; Hastings et al.,
2005b). However, in competing analyses problem behaviours in the child were no
longer significant in the prediction of depression or anxiety. It is likely that whether or
not an association emerges between the extent of behaviour problems and parental
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distress depends on what other variables have been included in the analyses. After all,
there were large case control group differences in parents’ reports of their children’s
behaviour problems in the present study. It is just that other variables better accounted
for group differences in depression and anxiety and depression and anxiety per se. It
is possible that children’s behaviour problems influence parental depression and
anxiety largely through parents’ perceptions of the burden they impose. Behaviour
problems and caregiver burden were highly correlated in the sample as a whole (r =
.76).
Throughout our analyses, caregiver burden emerged as the most consistent and
robust predictor of both symptomatology and possible pathology. Thus, burden would
appear to be as potent a source of distress for parents of intellectually disabled children
as it has been observed to be for other caregiver groups (Bibou-Nakou, Dikaiou, &
Bairactaris, 1997; Clyburn et al., 2000; Wade et al., 1998; Vedhara et al., 2002).
Caregiver burden is a broad concept encompassing feelings of embarrassment and guilt,
a sense of entrapment, resentment, and the experience of loss and isolation from society
(Zarit et al., 1980). A recent principal components analysis distilled three dimensions
of burden from the scale used in the current study: negative social and personal
consequences, psychological burden, and guilt (Ankri, et al., 2005). The first of these
proved to be the strongest predictor of depressive symptomatology in parents caring for
an intellectually disabled child, whereas the last was the only significant predictor of
anxiety scores. Thus, it would appear that symptoms of depression are manifest when
parents feel that their social and personal lives are constrained and disrupted as a result
of their caring role. There is indirect evidence in favour of this contention. Parents of
children with Down’s syndrome and autism were found to experience more distress
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when their social and work life was restricted as a result of their caring role (Hare, et
al., 2004; Roach, Orsmond, & Barratt, 1999; Shearn & Todd, 2000). Similarly, parents
of children with pervasive developmental disorders were found to have a poorer quality
of life, compared to controls, when their social relationships were impaired (Mugno,
Ruta, D'Arrigo, & Mazzone, 2007).
Originating in family stress research, the ambiguous loss theory (Boss, Caron,
Horbal, & Mortimer, 1990) considers that many parents of children with autism
experience a sense of ambiguous loss. Since caring in this context is neither stable nor
predictable, parents struggle to manage and tolerate this burden of ambiguity. The
identity loss, consequent on parents’ failure to separate their own identity from that of
their child, results in distress. Ambiguity about roles and responsibilities has been
found to contribute to depressive symptomatology in caregivers of dementia patients
(Boss et al., 1990). More telling in the current context, identity ambiguity in parents
of children with intellectual disabilities, but not the severity of autism spectrum
disorder symptoms (e.g communication, social interaction, and restricted/repetitive
interests, was a significant predictor of depressive symptoms (O'Brien, 2007).
In contrast, guilt was most the potent dimension of caregiver burden to predict
anxiety scores in these parents. This finding is broadly consistent with the results of
previous studies. A number of studies have observed that the parents of children with
intellectual disabilities who reported feelings of guilt also indicated that they lacked
confidence in their parenting abilities and decision-making which, in turn, was
associated with increased distress, including anxiety (Benderix, Nordstrom, & Sivberg,
2006; Hedov et al., 2002; Hilton, Hunt, & Petticrew, 2007; Lenhard, Breitenbach,
Ebert, Schindelhauer-Deutscher, & Henn, 2005).
21
The current study has a number of limitations. First, the data are cross-sectional.
Accordingly, the high levels of distress observed in those parents caring for
intellectually disabled children may be transitory. However, there is evidence that the
distress observed in this population persists over time (Dyson, 1993; Glidden &
Schoolcraft, 2003). Second, our sample size might be regarded as small. Parents of
intellectually disabled children are, for obvious reasons, notoriously difficult to recruit
for research purposes and this study is of the same order of magnitude of many of the
other published case control studies (Padeliadu, 1998; Roach et al., 1999; Weiss,
2002). Third, women outnumbered men, but this is hardly surprising since they
predominate as primary caregivers. Importantly, the ratio of women to men was
almost identical in the two parental groups. Finally, employment outside the home and
age differentiated the groups. However, the main associations were still evident
following adjustment for these variables.
In summary, relative to parents of typically developing children, parents caring for
intellectually disabled children reported high levels of depression and anxiety
symptoms. Further, the majority of these parents met the established criteria for
possible clinical depression and/or anxiety. The strongest and most consistent
predictor of group differences in distress, as well as individual variations in distress
within the group of parents with intellectually disabled children, was caregiver burden.
Analyses of its component dimensions indicated that the negative social and personal
consequences of caregiving were associated with depression, whereas guilt was
associated with anxiety. This suggests that psychosocial interventions for this
population might be tailored depending on how the distress presents itself as
depression, anxiety, or both, in the individual caregiver.
22
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31
Acknowledgements
The authors would like to express their appreciation to Autism West-Midlands, Down
Syndrome Association and Baljit Nhal from Birmingham Children’s Hospital for their
help with the recruitment process. A special thanks is also extended to the parents
caring for children with intellectual disabilities and the parents caring for typically
developing children who made this research possible.
32
Tab
le 1
. D
emo
gra
phic
ch
arac
teri
stic
s an
d c
hil
d c
are
resp
onsi
bil
itie
s of
par
enta
l gro
ups
C
ases
(N
= 3
2)
Contr
ols
(N
= 2
9)
Tes
t of
dif
fere
nce
Sex
(F
emal
e)
24 (
75%
) 20 (
69%
) χ2
(1)
= 0
.06, p =
.81
Mar
ital
Sta
tus
(Par
tner
ed)
28 (
88%
) 20 (
70%
) χ2
(1)
= 2
.11, p =
.15
Eth
nic
ity (
Cau
casi
an)
29 (
91%
) 26 (
90%
) χ2
(1)
= 0
.00, p =
1.0
0
Occ
upat
ional
sta
tus
(Pro
fess
ional
) 15 (
47%
) 16 (
55%
) χ
2 (
1)
= 0
.15, p =
.70
Curr
entl
y e
mplo
yed
outs
ide
the
hom
e
22 (
69%
) 29 (
100%
) χ2
(1)
= 7
.19, p =
.007
Mea
n a
ge
(SD
) yea
rs
4
2.8
(5.7
8)
3
9.9
(4.3
6)
F
(1,5
9)
= 4
.76, p =
.0
3
Mea
n b
od
y m
ass
index
(S
D)
kg/m
2
26.8
(4.2
7)
2
4.7
(4.1
0)
F
(1,5
6)
= 3
.80, p =
.0
6
Pri
mar
y c
areg
iver
25 (
78%
) 21 (
72%
) χ
2 (1
) =
0.0
5, p
= .83
Mea
n a
ge
of
mai
n c
are
reci
pie
nt
(SD
) yea
rs
11.2
(3.9
9)
8
.9 (
4.5
7)
F
(1,5
4)
= 3
.88, p =
.0
6
33
Table 2. Symptoms of depression and anxiety by parent group
Cases (N = 32)
Control (N = 29)
Mean depression score (SD) 8.6 (3.92) 3.2 (2.31)
Mean anxiety score (SD) 11.0 (4.40) 5.0 (2.44)
Depression score ≥ 8 (%) 20 (63%) 2 (7%)
Anxiety score ≥ 8 (%) 24 (75%) 3 (10%)
34
Table 3. Social support, sleep quality, child problem behaviours, caregiving burden by
parent group
Cases (N = 32)
Control (N = 29)
Mean social support score (SD) 31.3 (9.76) 37.9 (10.37)
Mean sleep quality score (SD) 10.0 (2.48) 7.1 (2.09)
Mean child behaviour problem score (SD) 22.9 (5.88) 9.9 (4.89)
Mean caregiver burden score (SD) 44.0 (14.26) 22.9 (10.67)
35
Figure captions
Figure 1. Mediation analysis of the association between parental group and depressive
symptomatology for child problem behaviours, sleep quality and caregiver burden:
statistics are standardised regression coefficients
Figure 2. Mediation analysis of the association between parental group and anxiety
scores for child problem behaviours, sleep quality and caregiver burden: statistics are
standardised regression coefficients
36
Care
burden
Depression
score
Parental
groups
.31
.63 .53
Sleep
quality
Depression
score
Parental
groups
.41
.54 .44
Child
behaviour
Depression
score
Parental
groups
Depression
score
Parental
groups
.64
.32
.77 .42
37
Care
burden
Anxiety
score
Depression
Parental
groups
.29
.63 .60
Child
behaviours
Anxiety
score
Parental
groups
Anxiety
score
Parental
groups
.66
.40
.77 .35
Sleep
quality
Anxiety
score
Parental
groups
.45
.54 .38