Research in Developmental Disabilities 35 (2014) 814–825
Contents lists available at ScienceDirect
Research in Developmental Disabilities
The emotional and behavioural functioning of siblings of children with special health care needs across childhood Rebecca Giallo a,b,c,*, Rachel Roberts d, Eric Emerson e, Catherine Wood f, Susana Gavidia-Payne b a
Parenting Research Centre, 5/232 Victoria Parade, East Melbourne, Victoria 3002, Australia RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia Murdoch Childrens Research Institute, Royal Children’s Hospital, Flemington Road, Parkville, Victoria 3052, Australia d School of Psychology, The University of Adelaide, Level 4, Hughes Building, South Australia 5005, Australia e Centre for Disability Research and Policy, The University of Sydney, Sydney, New South Wales 2006, Australia f Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 15 November 2013 Received in revised form 13 January 2014 Accepted 17 January 2014 Available online 7 February 2014
This study examined the emotional and behavioural functioning of siblings of children with special health care needs identified in the Longitudinal Study of Australian Children (LSAC). Of the 106 siblings identified, 15–52% had emotional and behavioural difficulties in the at-risk or clinical range on the parent-reported Strengths and Difficulties Questionnaire (SDQ) subscales when aged 4–5 (wave 1), 6–7 (wave 2), 8–9 (wave 3) and 10–11 years (wave 4). After controlling for differences in socio-economic position, siblings had significantly higher difficulties on all subscales than their peers without a brother or sister with a special health care need at most time points. Latent growth modelling revealed little change in emotional and behavioural symptoms for siblings across childhood, while behavioural symptoms decreased for their peers. These findings suggest that some siblings are at heightened risk of emotional and behavioural difficulties across childhood, underscoring the importance of assessing and promoting the wellbeing of all family members when providing services to children with special health care needs. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Special health care needs Siblings Emotional and behavioural difficulties Mental health Childhood
Several systematic reviews have reported increased emotional and behavioural difficulties among siblings of children with special health care needs such as disabilities and chronic health conditions including learning difficulties, speech and language impairments, and physical and sensory disabilities (Blakemore, Strazdins, & Gibbings, 2009; Burton & Parks, 1994; Cox, Marshall, Mandieco, & Olsen, 2003; Giallo, Baldwin, Thompson, & Schuster, 2009; Guite, Lobato, Kao, & Plante, 2004; Rossiter & Sharpe, 2001; Vermaes, van Susante, & van Bakel, 2012). These reviews highlight that the magnitude of negative effects are small, and that there is a high degree of inconsistency across studies. Some studies have reported positive outcomes such as increased self-control (Mandleco, Olsen, Dyches, & Marshall, 2003), tolerance and understanding (Mulroy, Robertson, Aiberti, Leonard, & Bower, 2008). The variation in outcomes reported across studies is in part likely due to a broad range of sibling, family, peer and social contextual factors associated with siblings’ emotional-behavioural functioning. Some key risk factors associated with adverse
* Corresponding author at: Parenting Research Centre, Level 5, 232 Victoria Parade, East Melbourne, Victoria 3002, Australia. Tel.: +61 3 8660 3500; fax: +61 3 8660 3599. E-mail address: [email protected] (R. Giallo). 0891-4222/$ – see front matter ß 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ridd.2014.01.017
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outcomes for siblings include various demographic characteristics such as sibling age, gender and birth order (Cuskelly & Gunn, 2006; Rossiter & Sharpe, 2001; Vermaes et al., 2012), severity of the condition (Vermaes et al., 2012), poor parent mental health (Fisman, Wolf, Ellison, & Freeman, 2000) and family functioning (Giallo & Gavidia-Payne, 2006; Mandleco et al., 2003). The variation in outcomes reported across studies is also likely associated with methodological differences in research design such as the disability of interest, the inclusion of a comparison sample or normative data, the use of parent or sibling report, and the psychological outcomes assessed. Furthermore, the existing literature is limited on four counts: (1) the use of nonrepresentative convenience samples; (2) the almost exclusive reliance on cross-sectional designs; (3) the broad age ranges sampled; and (4) the failure to take account of socioeconomic differences between families of children with and without disabilities when comparison samples are included. These issues will be briefly discussed below. The varied findings are also in part due to methodological differences across studies. For instance, the vast majority of available studies are based on cross-sectional designs with small convenience samples of siblings. To date, only one population-based study has reported on the mental health of siblings. In the Ontario Child Health Study in Canada, 2330 siblings (aged 4–16 years) of children with developmental disabilities were identified among 3294 children in the general population (Cadman, Boyle, & Offord, 1988). Siblings were found to be at a very small risk of having one or more psychiatric problems, and were no more likely to have a psychiatric problem than their peers. A limitation of this study was that it focused on identifying adjustment difficulties warranting a psychiatric diagnosis, and may underestimate the extent to which siblings do experience a range of social, emotional and behavioural difficulties. Another limitation of previous research is the very wide age range of siblings represented, often spanning early childhood to late adolescence. Such studies may lack sensitivity to developmental differences in adjustment that may occur. Although a recent meta-analysis of 56 studies found that older siblings of children with high care demands that affect daily functioning were at greater risk of low self-esteem and self-concept than younger siblings (Vermaes et al., 2012), it remains unclear whether there are periods of heightened risk of mental health difficulties across childhood and adolescence. Generally, very little is known about the trajectory of siblings’ emotional and behavioural development over time. To date, few longitudinal studies tracking outcomes for siblings have been published. For instance, Breslau and Prabucki (1987) conducted a longitudinal study of 192 siblings of children with disabilities aged 6–18 years at the time of the initial assessment. At the 5-year follow-up, siblings were reported to have more problems with aggression, depression and social isolation than at the initial assessment. Depression symptoms were more likely to persist over time for siblings of children with a disability compared to siblings of children without a disability. In another longitudinal study of 137 siblings, internalising and externalising adjustment problems were more likely to persist for siblings of children with a Pervasive Developmental Disorder than for siblings of children with Down syndrome and typically developing children over a 3-year period (Fisman et al., 2000). While these findings suggest that emotional and behavioural difficulties may persist for some siblings, they are typically based on unrepresentative North American convenience samples, the results of which may not generalise to other countries. Furthermore, both studies assessed emotional and behavioural functioning at two time points for siblings representing a diverse age range, which may not be sensitive to developmental stages and transition points for siblings across childhood and adolescence. Longitudinal studies that measure outcomes for siblings at multiple time points across childhood and adolescence would provide a better understanding of the trends and change in emotional and behavioural functioning over time. Such research may provide important information about periods of heightened risk of psychosocial difficulties, and inform the development of timely and relevant interventions and support to promote the wellbeing of siblings. Another key issue rarely addressed in research comparing families of children with special health care needs with other families is the role of social and economic circumstances contributing to differences in outcomes between them. It is well established that families of children with disabilities are significantly more likely than families of typically developing or well children to experience economic hardships and have access to fewer social resources (Emerson & Hatton, 2007; Hatton & Emerson, 2009). These broader differences in social and economic circumstances have been shown to partially account for differences between families of children with disabilities and other families on a range of outcomes including parental mental health (Emerson & Llewellyn, 2008; Emerson et al., 2010). The role of socioeconomic circumstances should also be considered in sibling research. To date, there is a paucity of studies investigating the association between socio-economic functioning and sibling outcomes. The research that is available has reported mixed findings. For example, some studies have found that family income is not related to the adjustment of siblings of children with Down syndrome or chronic illness (Thompson, 1994; Van Riper, 2000), while another study revealed that socioeconomic disadvantage was associated with increased emotional and behavioural difficulties among siblings of children with disabilities (Giallo & Gavidia-Payne, 2006). The conflicting results across studies might be due to methodological differences in measurement of socioeconomic circumstances, but may also be reflective of these small convenience samples which are generally more highly educated and not representative of more economically disadvantaged families. To address these research gaps, the present study sought to examine the course of emotional and behavioural functioning for siblings of children with special health care needs identified in a nationally representative longitudinal cohort study of Australian children. We have used ‘special health care needs’ as a broad term used to refer to children who have disabilities and chronic health conditions including learning difficulties, speech and language impairments, and physical and sensory disabilities. The specific aims of the study were to: (a) estimate the proportion of siblings who have a brother or sister with special health care needs; (b) estimate the proportion of siblings of children with special health care needs experiencing
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emotional and behavioural symptoms at the at-risk or clinical range at ages 4–5, 6–7, 8–9 and 10–11 years; (c) compare emotional and behavioural functioning of siblings of children with special health care needs to children who do not have a brother or sister with special health care needs at each time point, controlling for the influence of socioeconomic position; and (d) compare the trajectories of emotional and behavioural functioning across childhood for siblings of children with special health care needs to children who do not have a brother or sister with special health care needs while accounting for the influence of socioeconomic disadvantage. 1. Method 1.1. Study design and sample Data were drawn from waves 1–4 of the Growing up in Australia: Longitudinal Study of Australian Children (LSAC) Kindergarten or K cohort. The Australian Institute of Family Studies Ethics Committee approved each wave of the study, and the sampling design and field methods are described extensively elsewhere (Soloff, Lawrence, & Johnstone, 2005). In short, a two-stage sample design was used where approximately 10% of all postcodes were selected, and then a number of children proportional to population size were randomly selected from each postcode using Australia’s universal health insurance (Medicare) database, which includes over 90% of all Australian children. The K-cohort was recruited in 2004 and consisted of 4983 children aged 4–5 years (59% response rate). Sample characteristics were broadly representative of children and parents in the Australian population with marginal differences for mothers who completed year 12 were over-represented, and children form single parents families, non-English speaking backgrounds, and lower income families were underrepresented (Soloff et al., 2005). The cohort was reassessed when children were aged 6–7, 8–9, and 10–11 years. At wave 4 when the children were aged 10–11 years, 82% remained in the study. Retention was marginally lower for children with less highly educated parents and from non-English speaking background (Daraganova & Sipthorp, 2001). The sample for the present study included children who had data for the measure of emotional and behavioural functioning on at least three of the four waves. 1.2. Measures Special health care needs information for all children in the family were provided by the primary caregiver. At each wave, they were asked to indicate if their children had a medical condition or disability, the nature of the condition or disability (i.e., sight problems, speech problems, difficulty learning or understanding, disfigurement or deformity, long term effects of head injury) whether they had the condition or disability for 6 months or more, and whether it restricted their everyday activities. For the purpose of this study, a child was identified with special health care needs if they met the criteria for each of the following: (a) had a medical condition or disability at wave 1; (b) had a condition for 6 months or more; and (c) had a condition or disability on at least three of the four waves of data collection. Children’s emotional and behavioural functioning at all waves was measured using the Strengths and Difficulties Questionnaire – Parent Report version (SDQ; Goodman, 2001). The primary caregiver of the ‘study’ child was asked to rate 25 items (e.g., ‘‘Often complains of headaches, stomach aches or sickness’’, ‘‘Often loses temper’’) on a 3-point scale ranging from 0 ‘‘Not true’’ to 2 ‘‘Certainly true’’. There are five subscales including Conduct Problems, Hyperactivity, Emotional Symptoms, Peer Problems, and Prosocial Behaviour. It is also possible to identify children in the normal, borderline (referred to as ‘‘at risk’’ in the current study), and abnormal (referred to ‘‘clinical’’ in the current study) based on Australian norms (see http:// www.sdqinfo.com). The SDQ is being increasingly used for clinical assessment, outcome evaluation and epidemiological research studies. It has advantages over other well established scales such as the Child Behaviour Checklist including shorter administration time, focus on child strengths as well as difficulties, and high acceptability by respondents (Goodman & Scott, 1999). The SDQ has had extensive psychometric evaluation including with Australian samples, in which moderate to strong internal consistency and test-retest reliability reported (Hawes & Dadds, 2004). Cronbach’s a for the current sample ranged from .5 (Peer Problems at wave 1) to .8 (Hyperactivity at wave 2) across subscales and waves. Demographic information pertaining to ‘study’ children’s age, gender, country of birth, Aboriginal and Torres Strait Islander (ATSI) status and language spoken at home was provided by the primary caregiver. Socioeconomic position (SEP) was rated using a composite variable, ranking each family’s relative SEP based on parental income, education and occupational prestige (Brand & Brennan, 2009). Families with a standardised score at or below the 25th percentile were classified as ‘low’ SEP, those above the 75th percentile were classified as ‘high’ SEP, and the remainder were classified as ‘medium’ SEP. Continuous scores were used in all adjusted analyses. 1.3. Data analysis strategy Descriptive statistics and comparisons between siblings of children with a special health care need and their same age peers on each of the SDQ subscales controlling for socioeconomic position at each wave were conducted using multivariate analyses of covariance (MANCOVA). Latent growth models for each of the SDQ subscales were estimated separately to assess the course of symptoms for siblings of children with special health care needs and their same age peers using MPlus Version
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6 (Muthen & Muthen, 1998–2011). This involved creating latent factors to represent the initial or baseline levels of a variable (i.e., the intercept) and the trajectory or change in that variable over time (i.e., the slope). The intercept factor was created with a fixed loading of 1.0 at each wave, while the slope factor was created with fixed values to each time point (e.g., loadings of 0, 1.0, 2.0 and 3.0 for waves 1, 2, 3 and 4 respectively). All models were estimated using robust maximum likelihood estimation to account for multivariate non-normality, and assessed using the chi-square test (x2), and other practical fit indices including Tucker-Lewis Index (TLI), the Comparative Fit Index (CFI), and Root Mean Square Error of Approximation (RMSEA). Indices for the TLI and CFI should exceed 0.90 for an acceptable fit (Bentler, 1990), and values close to or below 0.05 for the RMSEA were considered acceptable (Hu & Bentler, 1999). Multiple group analyses were conducted to compare the SDQ subscale trajectories for siblings of children with special health care needs and their same age peers. The analyses were repeated to account for socioeconomic position. For each analysis, a model with all parameters freely estimated between groups (unconstrained model) was compared to a model with all parameters forced to be equal between the groups (constrained model). The Satorra–Bentler scaled chi-square difference test for the MLR estimation method as outlined on the Mplus website (www.statmodel.com/chidiff.shtml) was conducted to assess whether each of the trajectories significantly differed by group. 2. Results 2.1. Sample characteristics Of the 4983 children recruited into the K cohort, 1046 (21%) were excluded because they had no SDQ data for at least three of the four waves. Children and their families with incomplete data were significantly more likely to speak a language other than English at home and be socioeconomically more disadvantaged than those without missing data (p < .001). The final sample consisted of 3937 children and their demographic characteristics at wave 1 are presented in Table 1. Of these, 104 (2.6%) children had a brother or sister with a medical condition lasting for 6 months or longer at least three of the four waves. Demographic characteristics for siblings of children with a special health care condition and their same age peers are presented in Table 1. There were 422 (11%) children in the latter group that did not have a brother or sister at all, and they did not significantly differ from children who did have a brother or sister on the demographic characteristics. There were also no significant differences between siblings of children with special health care needs and their same age peers on each of the
Table 1 Demographic characteristics for final sample. Demographic characteristic
Child (sibling) characteristics Gender – female Agea Wave 1 Wave 2 Wave 3 Wave 4 Born in Australia English primarily spoken at home Aboriginal or Torres Strait Islander Attends school
Siblings of children with special health care needs (n = 104) n (%)
Same age peers without a brother or sister with special health care needs (n = 3833) n (%)
Total sample (n = 3937) n (%)
x2 or t
50 (48.1%)
1868 (47.4%)
1918 (48.7%)
0.12
4.14 (0.35) 6.29 (0.46) 8.21 (0.41) 10.23 (0.41) 102 (98.1%) 99 (95.1%) 5 (4.8%) 101 (97.1%)
4.17 (0.38) 6.29 (0.45) 8.26 (0.44) 10.20 (0.43) 3685 (96%) 3447 (89.9%) 100 (2.6%) 3698 (96.5%)
4.17 (0.38) 6.29 (0.45) 8.26 (0.44) 10.20 (0.43) 3787 (96.2%) 3546 (90.1%) 105 (2.7%) 3799 (96.5%)
0.73 0.08 1.09 0.73 1.06 3.14 2.70 0.12
949 (24.8%) 1920 (50.1%) 964 (25.2%) 2.44 (0.97) 3420 (89.2%)
982 (24.9%) 1973 (50.1%) 982 (24.9%) 2.45 (0.98) 3510 (89.2%)
4.49
– – – –
77 (74.0%) 17 (16.3%) 5 (4.8%) 5 (4.8%)
– – – –
3729 (97.3%) 35.12 (5.22) 2369 (61.8%) 2333 (60.9%)
3832 (97.3%) 35.12 (5.21) 2427 (61.7%) 2392 (60.8%)
1.20 0.45 4.95 1.34
Family characteristics Socioeconomic position Low 33 (31.7%) Medium 53 (50.9%) High 18 (17.3%) Number of children in householda 2.96 (1.22) Family structure – two parent family 90 (86.5%) Number of children in the family who have a special health care need One 77 (74.0%) Two 17 (16.3%) Three 5 (4.8%) Four 5 (4.8%) Parental informant characteristics Gender – female Agea Education level – year 12 and above Employed – part or full-time a Mean (SD). * p < .001.
103 (99.0%) 34.88 (5.18) 58 (55.8%) 59 (56.7%)
5.36* 0.83
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Table 2 Characteristics of children with special health care needs. Characteristic
n (%)
Number of children with a special health care needs at wave 1 Gender – female Special health care condition at wave 1 Sight problems Hearing problems Speech problems Blackouts, fits or loss of consciousness Difficulty learning or understanding Limited use of arms or fingers, legs or feet Disfigurement or deformity Has difficulty breathing Mental illness needing help or supervision Long term effects of head injury Conditions lasting 6 months or morea Wave 1 Wave 2 Wave 3 Wave 4 Restricted daily activitiesa Wave 2 Wave 3 Wave 4
146 (100.0%) 122 (83.6%)
a
12 (8.2%) 20 (13.7%) 39 (26.7%) 2 (1.4%) 36 (24.7%) 6 (4.1%) 1 (0.7%) 2 (1.4%) 4 (2.7%) 6 (4.1%) 146 (100%) 81 (55.5%) 120 (82.2%) 113 (77.4%) 57 (39.0%) 35 (24.0%) 33 (22.6%)
Information not available at wave 1.
demographic characteristics, except for the mean number of children in the family was greater for siblings of children with special health care needs. Although there were more families of children with special health care needs in the lowest SEP group than families of children without special health care needs, this was not statistically significant. Table 2 presents the characteristics of the 146 children identified with special health care needs. The majority were female, and the most common conditions were speech problems, having difficulties learning or understanding, and hearing problems. The condition was lasting 6 months or more for the majority of children at each wave, and restricted the daily activities of approximately a quarter to a third of the sample. 2.1.1. Missing data Missing data on the SDQ subscales across the four waves ranged from 0.2% (Emotional Symptoms wave 1) to 12.3% (Hyperactivity wave 3). Missing data were imputed using full information maximum likelihood in MPlus Version 6.0 (Muthen & Muthen, 1998–2011). 2.1.2. Siblings of children with special health care needs in the at-risk or clinical ranges of the Strengths and Difficulties Questionnaire subscales at each wave The proportion of siblings reported to have Emotional Symptoms in the ‘‘at risk’’ or ‘‘clinical’’ range increased across the waves (wave 1: 19.2%, wave 2: 15.5%, wave 3: 25.3%, and wave 4: 29.2%). The number of siblings in the at-risk or clinical range for Peer Problems also tended to increase (wave 1: 23.1%, wave 2: 23.8%, wave 3: 31.8%, wave 4: 28.2%). For Conduct Problems, marked problems were highest at wave 1 (52.4%), and then stayed consistent from waves 2–4 (wave 2: 27.7%, wave 3: 30.6%, wave 28.2%). Approximately one quarter of the sample had Hyperactive/Inattention symptoms in the at-risk or clinical range across the four waves (wave 1: 23.1%, wave 2: 24.8%, wave 3: 27.7%, wave 4: 24.3%). Finally, the proportion of siblings in the at-risk or clinical range dropped slightly over time for Prosocial Behaviour (wave 1: 20.2%, wave 2: 17.5%, wave 3: 17.1%, wave 4: 14.7%). 2.1.3. Comparisons between siblings of children with special health care needs and their same age peers on the Strengths and Difficulties Questionnaire subscales at each wave Comparisons between siblings of children with special health care needs and their peers participating in LSAC on each of the SDQ subscales were made, with and without controlling for socioeconomic position, using multivariate analyses of covariance (MANCOVA) at each wave. The multivariate results without controlling for SEP revealed significant differences between siblings of children with special health care needs and their peers at all ages; 4–5 years (Wilks D = 1.00, F(5, 4053) = 4.11, p = .001, multivariate h2 = .005), 6–7 years (Wilks D = 1.00, F(5, 3819) = 3.26, p = .006, multivariate h2 = .004), 8–9 years (Wilks D = 1.00, F(5, 3469) = 2.56, p = .026, multivariate h2 = .004), and 10–11 years (Wilks D = 1.00, F(5, 4028) = 3.92, p = .001, multivariate h2 = .005). The multivariate results were similar when controlling for SEP, except there were no significant differences between the groups at age 8–9 years. The results were as follows; 4–5 years (Wilks D = 99, F(5, 4044) = 3.06, p = .009, multivariate h2 = .004), 6–7 years (Wilks D = 99, F(5, 3810) = 2.72, p = .018, multivariate h2 = .004), and 10–11 years (Wilks D = 99, F(5, 4018) = 3.09, p = .009, multivariate h2 = .004). Table 3 displays the descriptive and univariate results for each of the subscales
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Table 3 Mean comparisons between siblings of children with special health care needs and their peers on the Strengths and Difficulties Questionnaire subscales at each wave while controlling for socioeconomic position using MANCOVA. Siblings of children with special health care needs (N = 104)
Same age peers without a brother or sister with a special health care need (N = 3810)
Univariate
M (SD)
M (SD)
F
p
(95% CI)
Wave 1: 4–5 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
2.11 2.92 4.04 1.80 7.26
(1.90) (2.30) (2.56) (1.72) (1.88)
1.65 2.42 3.43 1.60 7.76
(1.63) (2.00) (2.25) (1.52) (1.78)
6.99 5.27 5.91 0.93 7.32
.008 .022 .015 .334 .007
0.28 0.25 0.27 0.13 0.28
(0.09, 0.47) (0.06, 0.44) (0.08, 0.46) (0.06, 0.33) (0.47, 0.09)
Wave 2: 6–7 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
1.75 1.87 3.87 1.52 7.75
(1.66) (1.71) (2.76) (1.57) (1.92)
1.58 1.43 3.27 1.45 8.26
(1.70) (1.47) (2.03) (1.55) (1.68)
0.55 7.45 5.38 0.04 8.63
.457 .006 .020 .837 .003
0.10 0.30 0.29 0.05 0.30
(0.10, 0.30) (0.10, 0.49) (0.10, 0.49) (0.15, 0.24) (0.50, 0.11)
Wave 3: 8–9 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
1.99 1.66 3.95 1.84 7.95
(1.95) (1.79) (2.68) (1.93) (2.05)
1.56 1.29 3.15 1.43 8.26
(1.75) (1.44) (2.33) (1.61) (1.72)
4.02 3.92 7.65 3.93 2.30
.045 .048 .006 .048 .130
0.24 0.26 0.34 .25 0.38
(0.03, 0.46) (0.04, 0.47) (0.12, 0.56) (0.03–0.47) (0.60, 0.16)
Wave 4: 10–11 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
2.35 1.81 3.91 1.89 8.01
(2.23) (1.82) (2.84) (2.18) (1.92)
1.91 1.33 3.17 1.49 8.52
(1.94) (1.47) (2.34) (1.71) (1.65)
4.37 9.04 8.43 4.44 9.38
.037 .003 .004 .035 .022
0.23 0.32 0.31 0.23 0.31
(0.03, 0.42) (0.13, 0.52) (0.12, 0.51) (0.04, 0.43) (0.50, 0.11)
Cohen’s d
accounting for SEP. Siblings of children with special health care needs had significantly higher emotional, conduct, hyperactivity and peer problems than their same age peers at most waves except for peer problems at wave 1 and 2 and emotional symptoms at wave 2. Siblings of children with special health care needs had significantly fewer prosocial behaviours than their peers at waves 1, 2 and 4. All these differences were associated with small effect sizes. 2.1.4. Latent growth models for siblings of children with special health care needs and their same age peers on each of the SDQ subscale scores across childhood Prior to conducting multiple group analyses to compare emotional and behavioural functioning trajectories of siblings of children special health care needs and their peers, a series of two-factor latent growth models for each of the SDQ subscale scores were conducted separately for each group. All models were estimated using robust maximum likelihood estimate to adjust the fit indices and parameter estimates to account for non-normality. The model fit statistics are presented in Table 4. All models were an acceptable fit to the data, except Conduct Problems for both groups. It is possible that the course of conduct problems is not linear across time as there was some evidence that conduct problems are high at 4–5 years, decrease slowly across childhood then increase again at 10–11 years. Additional waves of data may be required to reliably model conduct problems over early to late childhood. The multiple group analyses presented in Table 5 revealed that there were significant differences between the groups for all SDQ subscales except for emotional symptoms. The pattern of results was similar when adjustment for the influence of socioeconomic position was made. Fig. 1 shows the SDQ subscale trajectories (estimated means at each time point) for siblings of children with special health care needs and their peers participating in LSAC, and Table 6 presents the standardised parameters for the latent growth models. The means of the intercepts were positive and significantly different from zero for all SDQ subscales for both groups. The variances of the intercepts were also significant indicating individual differences in the levels of emotional and behavioural functioning at wave 1. The intercepts for both groups were similar across the subscales. The means of all slopes on the SDQ subscales were significant for the same aged peers without a brother or sister with a special health care needs. Specifically, the slopes were positive for emotional symptoms and prosocial behaviour indicating that, on average, scores on these measures increased at a rate of .19 and .63 points each wave, respectively (also see Fig. 1). The slopes for hyperactivity and peer problems were negative, decreasing at a rate of .16 and .10 points each wave, respectively. For siblings of children with a special health care need, the only significant slope was for prosocial behaviour, with scores increasing at a rate of .47 points each wave. The variances of the slopes were significant for all subscales for children without a brother or sister with a special health care need and only significant for emotional symptoms, peer
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Table 4 Latent growth model fit statistics for the latent growth models for siblings of children with special health care needs and their peers on each of the SDQ subscales.
x2 (df) Siblings of children with a special health care need (n = 104) Emotional symptoms 20.63 (5)** Conduct problems 60.65 (6)*** Hyperactivity 14.08 (5)* Peer problems 5.61 (5) Prosocial behaviour 14.14 (5)*
CFI
TLI
RMSEA (90% CI)
.88 .50 .94 .99 .93
.83 .50 .92 .99 .92
.17 .30 .13 .03 .13
(.07–.22) (.23–.37) (.05–.22) (.00–.14) (.05–.22)
.96 .78 .98 .98 .94
.07 .17 .06 .05 .08
(.06–.08) (.15–.18) (.05–.07) (.03–.06) (.07–.10)
Same age peers without a brother or sister with a special health care need (n = 3833) Emotional symptoms 93.66 (5)*** .96 Conduct problems 526.47 (5)*** .82 Hyperactivity 75.25 (5)*** .99 Peer problems 44.18 (5)*** .99 Prosocial behaviour 137.27 (5)*** .95
Table 5 Multiple group analyses results for the latent growth models on each of the SDQ subscales accounting for and not accounting for socioeconomic position.
Emotional symptoms Unconstrained Constrained Hyperactivity Unconstrained Constrained Peer problems Unconstrained Constrained
Not accounting for socioeconomic position
Accounting for socioeconomic position
x2 (df)
x2 (df)
x2diff (df)a
125.94 (10)*** 146.08 (22)***
13.53 (12)ns
134.73 (14)*** 148.56 (28)***
22.28 (14)ns
89.30 (10)*** 194.45 (22)***
103.53 (12)***
112.33 (14)*** 218.83 (28)***
61.10 (14)***
54.22 (10)*** 83.28 (22)***
Prosocial behaviour Unconstrained Constrained
x2diff (df)a
59.43 (14)*** 89.91 (28)***
32.44 (12)**
160.10 (10)*** 227.84 (22)***
32.99 (14)**
164.35 (14)*** 239.00 (28)***
80.47 (12)***
105.21 (14)***
** p < .01. *** p < .001. ns not significant.
Table 6 Parameter estimates of the latent growth models for siblings of children with special health care needs and their same age peers on each of the SDQ subscales adjusting for socioeconomic position. Intercept mean
Slope mean
Siblings of children with a special health care need Emotional symptoms 1.84 (SE = .19)*** .15 (SE = .09) Hyperactivity 4.01 (SE = .26)*** .01 (SE = .09) *** Peer problems 1.32 (SE = .16) .16 (SE = .14) Prosocial behaviour 7.35 (SE = .19)*** .23 (SE = .07)**
Intercept variance 1.61 4.82 0.88 2.90
(SE = .59)** (SE = .89)*** (SE = .08)*** (SE = .50)***
Slope variance .30 .22 .97 .25
Same age peers without a brother or sister with a special health care need Emotional Symptoms 1.60 (SE = .03)*** .07 (SE = .01)*** 1.31 (SE = .07)*** .15 Hyperactivity 3.44 (SE = .04)*** .08 (SE = .02)*** 3.11 (SE = .12)*** .25 *** *** *** Peer Problems 1.47 (SE = .04) .10 (SE = .03) 0.93 (SE = .01) 1.00 Prosocial Behaviour 7.85 (SE = .03)*** .23 (SE = .01)*** 1.68 (SE = .08)*** .13
Intercept–slope covariance
(SE = .12)* .07 (SE = .21) (SE = .16) .04 (SE = .32) (SE = .04)*** .002 (SE = .21) ** (SE = .09) .37 (SE = .15)** (SE = .02)*** (SE = .02)*** (SE = .01)*** (SE = .02)***
.04 .17 .14 .18
SEP ! intercept .50 .30 .34 .21
SEP ! slope
(SE = .18)*** .06 (SE = .09) (SE = .32) .01 (SE = .10) ** (SE = .12) .16 (SE = .13) (SE = .25)
Contents lists available at ScienceDirect
Research in Developmental Disabilities
The emotional and behavioural functioning of siblings of children with special health care needs across childhood Rebecca Giallo a,b,c,*, Rachel Roberts d, Eric Emerson e, Catherine Wood f, Susana Gavidia-Payne b a
Parenting Research Centre, 5/232 Victoria Parade, East Melbourne, Victoria 3002, Australia RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia Murdoch Childrens Research Institute, Royal Children’s Hospital, Flemington Road, Parkville, Victoria 3052, Australia d School of Psychology, The University of Adelaide, Level 4, Hughes Building, South Australia 5005, Australia e Centre for Disability Research and Policy, The University of Sydney, Sydney, New South Wales 2006, Australia f Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 15 November 2013 Received in revised form 13 January 2014 Accepted 17 January 2014 Available online 7 February 2014
This study examined the emotional and behavioural functioning of siblings of children with special health care needs identified in the Longitudinal Study of Australian Children (LSAC). Of the 106 siblings identified, 15–52% had emotional and behavioural difficulties in the at-risk or clinical range on the parent-reported Strengths and Difficulties Questionnaire (SDQ) subscales when aged 4–5 (wave 1), 6–7 (wave 2), 8–9 (wave 3) and 10–11 years (wave 4). After controlling for differences in socio-economic position, siblings had significantly higher difficulties on all subscales than their peers without a brother or sister with a special health care need at most time points. Latent growth modelling revealed little change in emotional and behavioural symptoms for siblings across childhood, while behavioural symptoms decreased for their peers. These findings suggest that some siblings are at heightened risk of emotional and behavioural difficulties across childhood, underscoring the importance of assessing and promoting the wellbeing of all family members when providing services to children with special health care needs. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Special health care needs Siblings Emotional and behavioural difficulties Mental health Childhood
Several systematic reviews have reported increased emotional and behavioural difficulties among siblings of children with special health care needs such as disabilities and chronic health conditions including learning difficulties, speech and language impairments, and physical and sensory disabilities (Blakemore, Strazdins, & Gibbings, 2009; Burton & Parks, 1994; Cox, Marshall, Mandieco, & Olsen, 2003; Giallo, Baldwin, Thompson, & Schuster, 2009; Guite, Lobato, Kao, & Plante, 2004; Rossiter & Sharpe, 2001; Vermaes, van Susante, & van Bakel, 2012). These reviews highlight that the magnitude of negative effects are small, and that there is a high degree of inconsistency across studies. Some studies have reported positive outcomes such as increased self-control (Mandleco, Olsen, Dyches, & Marshall, 2003), tolerance and understanding (Mulroy, Robertson, Aiberti, Leonard, & Bower, 2008). The variation in outcomes reported across studies is in part likely due to a broad range of sibling, family, peer and social contextual factors associated with siblings’ emotional-behavioural functioning. Some key risk factors associated with adverse
* Corresponding author at: Parenting Research Centre, Level 5, 232 Victoria Parade, East Melbourne, Victoria 3002, Australia. Tel.: +61 3 8660 3500; fax: +61 3 8660 3599. E-mail address: [email protected] (R. Giallo). 0891-4222/$ – see front matter ß 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ridd.2014.01.017
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outcomes for siblings include various demographic characteristics such as sibling age, gender and birth order (Cuskelly & Gunn, 2006; Rossiter & Sharpe, 2001; Vermaes et al., 2012), severity of the condition (Vermaes et al., 2012), poor parent mental health (Fisman, Wolf, Ellison, & Freeman, 2000) and family functioning (Giallo & Gavidia-Payne, 2006; Mandleco et al., 2003). The variation in outcomes reported across studies is also likely associated with methodological differences in research design such as the disability of interest, the inclusion of a comparison sample or normative data, the use of parent or sibling report, and the psychological outcomes assessed. Furthermore, the existing literature is limited on four counts: (1) the use of nonrepresentative convenience samples; (2) the almost exclusive reliance on cross-sectional designs; (3) the broad age ranges sampled; and (4) the failure to take account of socioeconomic differences between families of children with and without disabilities when comparison samples are included. These issues will be briefly discussed below. The varied findings are also in part due to methodological differences across studies. For instance, the vast majority of available studies are based on cross-sectional designs with small convenience samples of siblings. To date, only one population-based study has reported on the mental health of siblings. In the Ontario Child Health Study in Canada, 2330 siblings (aged 4–16 years) of children with developmental disabilities were identified among 3294 children in the general population (Cadman, Boyle, & Offord, 1988). Siblings were found to be at a very small risk of having one or more psychiatric problems, and were no more likely to have a psychiatric problem than their peers. A limitation of this study was that it focused on identifying adjustment difficulties warranting a psychiatric diagnosis, and may underestimate the extent to which siblings do experience a range of social, emotional and behavioural difficulties. Another limitation of previous research is the very wide age range of siblings represented, often spanning early childhood to late adolescence. Such studies may lack sensitivity to developmental differences in adjustment that may occur. Although a recent meta-analysis of 56 studies found that older siblings of children with high care demands that affect daily functioning were at greater risk of low self-esteem and self-concept than younger siblings (Vermaes et al., 2012), it remains unclear whether there are periods of heightened risk of mental health difficulties across childhood and adolescence. Generally, very little is known about the trajectory of siblings’ emotional and behavioural development over time. To date, few longitudinal studies tracking outcomes for siblings have been published. For instance, Breslau and Prabucki (1987) conducted a longitudinal study of 192 siblings of children with disabilities aged 6–18 years at the time of the initial assessment. At the 5-year follow-up, siblings were reported to have more problems with aggression, depression and social isolation than at the initial assessment. Depression symptoms were more likely to persist over time for siblings of children with a disability compared to siblings of children without a disability. In another longitudinal study of 137 siblings, internalising and externalising adjustment problems were more likely to persist for siblings of children with a Pervasive Developmental Disorder than for siblings of children with Down syndrome and typically developing children over a 3-year period (Fisman et al., 2000). While these findings suggest that emotional and behavioural difficulties may persist for some siblings, they are typically based on unrepresentative North American convenience samples, the results of which may not generalise to other countries. Furthermore, both studies assessed emotional and behavioural functioning at two time points for siblings representing a diverse age range, which may not be sensitive to developmental stages and transition points for siblings across childhood and adolescence. Longitudinal studies that measure outcomes for siblings at multiple time points across childhood and adolescence would provide a better understanding of the trends and change in emotional and behavioural functioning over time. Such research may provide important information about periods of heightened risk of psychosocial difficulties, and inform the development of timely and relevant interventions and support to promote the wellbeing of siblings. Another key issue rarely addressed in research comparing families of children with special health care needs with other families is the role of social and economic circumstances contributing to differences in outcomes between them. It is well established that families of children with disabilities are significantly more likely than families of typically developing or well children to experience economic hardships and have access to fewer social resources (Emerson & Hatton, 2007; Hatton & Emerson, 2009). These broader differences in social and economic circumstances have been shown to partially account for differences between families of children with disabilities and other families on a range of outcomes including parental mental health (Emerson & Llewellyn, 2008; Emerson et al., 2010). The role of socioeconomic circumstances should also be considered in sibling research. To date, there is a paucity of studies investigating the association between socio-economic functioning and sibling outcomes. The research that is available has reported mixed findings. For example, some studies have found that family income is not related to the adjustment of siblings of children with Down syndrome or chronic illness (Thompson, 1994; Van Riper, 2000), while another study revealed that socioeconomic disadvantage was associated with increased emotional and behavioural difficulties among siblings of children with disabilities (Giallo & Gavidia-Payne, 2006). The conflicting results across studies might be due to methodological differences in measurement of socioeconomic circumstances, but may also be reflective of these small convenience samples which are generally more highly educated and not representative of more economically disadvantaged families. To address these research gaps, the present study sought to examine the course of emotional and behavioural functioning for siblings of children with special health care needs identified in a nationally representative longitudinal cohort study of Australian children. We have used ‘special health care needs’ as a broad term used to refer to children who have disabilities and chronic health conditions including learning difficulties, speech and language impairments, and physical and sensory disabilities. The specific aims of the study were to: (a) estimate the proportion of siblings who have a brother or sister with special health care needs; (b) estimate the proportion of siblings of children with special health care needs experiencing
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emotional and behavioural symptoms at the at-risk or clinical range at ages 4–5, 6–7, 8–9 and 10–11 years; (c) compare emotional and behavioural functioning of siblings of children with special health care needs to children who do not have a brother or sister with special health care needs at each time point, controlling for the influence of socioeconomic position; and (d) compare the trajectories of emotional and behavioural functioning across childhood for siblings of children with special health care needs to children who do not have a brother or sister with special health care needs while accounting for the influence of socioeconomic disadvantage. 1. Method 1.1. Study design and sample Data were drawn from waves 1–4 of the Growing up in Australia: Longitudinal Study of Australian Children (LSAC) Kindergarten or K cohort. The Australian Institute of Family Studies Ethics Committee approved each wave of the study, and the sampling design and field methods are described extensively elsewhere (Soloff, Lawrence, & Johnstone, 2005). In short, a two-stage sample design was used where approximately 10% of all postcodes were selected, and then a number of children proportional to population size were randomly selected from each postcode using Australia’s universal health insurance (Medicare) database, which includes over 90% of all Australian children. The K-cohort was recruited in 2004 and consisted of 4983 children aged 4–5 years (59% response rate). Sample characteristics were broadly representative of children and parents in the Australian population with marginal differences for mothers who completed year 12 were over-represented, and children form single parents families, non-English speaking backgrounds, and lower income families were underrepresented (Soloff et al., 2005). The cohort was reassessed when children were aged 6–7, 8–9, and 10–11 years. At wave 4 when the children were aged 10–11 years, 82% remained in the study. Retention was marginally lower for children with less highly educated parents and from non-English speaking background (Daraganova & Sipthorp, 2001). The sample for the present study included children who had data for the measure of emotional and behavioural functioning on at least three of the four waves. 1.2. Measures Special health care needs information for all children in the family were provided by the primary caregiver. At each wave, they were asked to indicate if their children had a medical condition or disability, the nature of the condition or disability (i.e., sight problems, speech problems, difficulty learning or understanding, disfigurement or deformity, long term effects of head injury) whether they had the condition or disability for 6 months or more, and whether it restricted their everyday activities. For the purpose of this study, a child was identified with special health care needs if they met the criteria for each of the following: (a) had a medical condition or disability at wave 1; (b) had a condition for 6 months or more; and (c) had a condition or disability on at least three of the four waves of data collection. Children’s emotional and behavioural functioning at all waves was measured using the Strengths and Difficulties Questionnaire – Parent Report version (SDQ; Goodman, 2001). The primary caregiver of the ‘study’ child was asked to rate 25 items (e.g., ‘‘Often complains of headaches, stomach aches or sickness’’, ‘‘Often loses temper’’) on a 3-point scale ranging from 0 ‘‘Not true’’ to 2 ‘‘Certainly true’’. There are five subscales including Conduct Problems, Hyperactivity, Emotional Symptoms, Peer Problems, and Prosocial Behaviour. It is also possible to identify children in the normal, borderline (referred to as ‘‘at risk’’ in the current study), and abnormal (referred to ‘‘clinical’’ in the current study) based on Australian norms (see http:// www.sdqinfo.com). The SDQ is being increasingly used for clinical assessment, outcome evaluation and epidemiological research studies. It has advantages over other well established scales such as the Child Behaviour Checklist including shorter administration time, focus on child strengths as well as difficulties, and high acceptability by respondents (Goodman & Scott, 1999). The SDQ has had extensive psychometric evaluation including with Australian samples, in which moderate to strong internal consistency and test-retest reliability reported (Hawes & Dadds, 2004). Cronbach’s a for the current sample ranged from .5 (Peer Problems at wave 1) to .8 (Hyperactivity at wave 2) across subscales and waves. Demographic information pertaining to ‘study’ children’s age, gender, country of birth, Aboriginal and Torres Strait Islander (ATSI) status and language spoken at home was provided by the primary caregiver. Socioeconomic position (SEP) was rated using a composite variable, ranking each family’s relative SEP based on parental income, education and occupational prestige (Brand & Brennan, 2009). Families with a standardised score at or below the 25th percentile were classified as ‘low’ SEP, those above the 75th percentile were classified as ‘high’ SEP, and the remainder were classified as ‘medium’ SEP. Continuous scores were used in all adjusted analyses. 1.3. Data analysis strategy Descriptive statistics and comparisons between siblings of children with a special health care need and their same age peers on each of the SDQ subscales controlling for socioeconomic position at each wave were conducted using multivariate analyses of covariance (MANCOVA). Latent growth models for each of the SDQ subscales were estimated separately to assess the course of symptoms for siblings of children with special health care needs and their same age peers using MPlus Version
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6 (Muthen & Muthen, 1998–2011). This involved creating latent factors to represent the initial or baseline levels of a variable (i.e., the intercept) and the trajectory or change in that variable over time (i.e., the slope). The intercept factor was created with a fixed loading of 1.0 at each wave, while the slope factor was created with fixed values to each time point (e.g., loadings of 0, 1.0, 2.0 and 3.0 for waves 1, 2, 3 and 4 respectively). All models were estimated using robust maximum likelihood estimation to account for multivariate non-normality, and assessed using the chi-square test (x2), and other practical fit indices including Tucker-Lewis Index (TLI), the Comparative Fit Index (CFI), and Root Mean Square Error of Approximation (RMSEA). Indices for the TLI and CFI should exceed 0.90 for an acceptable fit (Bentler, 1990), and values close to or below 0.05 for the RMSEA were considered acceptable (Hu & Bentler, 1999). Multiple group analyses were conducted to compare the SDQ subscale trajectories for siblings of children with special health care needs and their same age peers. The analyses were repeated to account for socioeconomic position. For each analysis, a model with all parameters freely estimated between groups (unconstrained model) was compared to a model with all parameters forced to be equal between the groups (constrained model). The Satorra–Bentler scaled chi-square difference test for the MLR estimation method as outlined on the Mplus website (www.statmodel.com/chidiff.shtml) was conducted to assess whether each of the trajectories significantly differed by group. 2. Results 2.1. Sample characteristics Of the 4983 children recruited into the K cohort, 1046 (21%) were excluded because they had no SDQ data for at least three of the four waves. Children and their families with incomplete data were significantly more likely to speak a language other than English at home and be socioeconomically more disadvantaged than those without missing data (p < .001). The final sample consisted of 3937 children and their demographic characteristics at wave 1 are presented in Table 1. Of these, 104 (2.6%) children had a brother or sister with a medical condition lasting for 6 months or longer at least three of the four waves. Demographic characteristics for siblings of children with a special health care condition and their same age peers are presented in Table 1. There were 422 (11%) children in the latter group that did not have a brother or sister at all, and they did not significantly differ from children who did have a brother or sister on the demographic characteristics. There were also no significant differences between siblings of children with special health care needs and their same age peers on each of the
Table 1 Demographic characteristics for final sample. Demographic characteristic
Child (sibling) characteristics Gender – female Agea Wave 1 Wave 2 Wave 3 Wave 4 Born in Australia English primarily spoken at home Aboriginal or Torres Strait Islander Attends school
Siblings of children with special health care needs (n = 104) n (%)
Same age peers without a brother or sister with special health care needs (n = 3833) n (%)
Total sample (n = 3937) n (%)
x2 or t
50 (48.1%)
1868 (47.4%)
1918 (48.7%)
0.12
4.14 (0.35) 6.29 (0.46) 8.21 (0.41) 10.23 (0.41) 102 (98.1%) 99 (95.1%) 5 (4.8%) 101 (97.1%)
4.17 (0.38) 6.29 (0.45) 8.26 (0.44) 10.20 (0.43) 3685 (96%) 3447 (89.9%) 100 (2.6%) 3698 (96.5%)
4.17 (0.38) 6.29 (0.45) 8.26 (0.44) 10.20 (0.43) 3787 (96.2%) 3546 (90.1%) 105 (2.7%) 3799 (96.5%)
0.73 0.08 1.09 0.73 1.06 3.14 2.70 0.12
949 (24.8%) 1920 (50.1%) 964 (25.2%) 2.44 (0.97) 3420 (89.2%)
982 (24.9%) 1973 (50.1%) 982 (24.9%) 2.45 (0.98) 3510 (89.2%)
4.49
– – – –
77 (74.0%) 17 (16.3%) 5 (4.8%) 5 (4.8%)
– – – –
3729 (97.3%) 35.12 (5.22) 2369 (61.8%) 2333 (60.9%)
3832 (97.3%) 35.12 (5.21) 2427 (61.7%) 2392 (60.8%)
1.20 0.45 4.95 1.34
Family characteristics Socioeconomic position Low 33 (31.7%) Medium 53 (50.9%) High 18 (17.3%) Number of children in householda 2.96 (1.22) Family structure – two parent family 90 (86.5%) Number of children in the family who have a special health care need One 77 (74.0%) Two 17 (16.3%) Three 5 (4.8%) Four 5 (4.8%) Parental informant characteristics Gender – female Agea Education level – year 12 and above Employed – part or full-time a Mean (SD). * p < .001.
103 (99.0%) 34.88 (5.18) 58 (55.8%) 59 (56.7%)
5.36* 0.83
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Table 2 Characteristics of children with special health care needs. Characteristic
n (%)
Number of children with a special health care needs at wave 1 Gender – female Special health care condition at wave 1 Sight problems Hearing problems Speech problems Blackouts, fits or loss of consciousness Difficulty learning or understanding Limited use of arms or fingers, legs or feet Disfigurement or deformity Has difficulty breathing Mental illness needing help or supervision Long term effects of head injury Conditions lasting 6 months or morea Wave 1 Wave 2 Wave 3 Wave 4 Restricted daily activitiesa Wave 2 Wave 3 Wave 4
146 (100.0%) 122 (83.6%)
a
12 (8.2%) 20 (13.7%) 39 (26.7%) 2 (1.4%) 36 (24.7%) 6 (4.1%) 1 (0.7%) 2 (1.4%) 4 (2.7%) 6 (4.1%) 146 (100%) 81 (55.5%) 120 (82.2%) 113 (77.4%) 57 (39.0%) 35 (24.0%) 33 (22.6%)
Information not available at wave 1.
demographic characteristics, except for the mean number of children in the family was greater for siblings of children with special health care needs. Although there were more families of children with special health care needs in the lowest SEP group than families of children without special health care needs, this was not statistically significant. Table 2 presents the characteristics of the 146 children identified with special health care needs. The majority were female, and the most common conditions were speech problems, having difficulties learning or understanding, and hearing problems. The condition was lasting 6 months or more for the majority of children at each wave, and restricted the daily activities of approximately a quarter to a third of the sample. 2.1.1. Missing data Missing data on the SDQ subscales across the four waves ranged from 0.2% (Emotional Symptoms wave 1) to 12.3% (Hyperactivity wave 3). Missing data were imputed using full information maximum likelihood in MPlus Version 6.0 (Muthen & Muthen, 1998–2011). 2.1.2. Siblings of children with special health care needs in the at-risk or clinical ranges of the Strengths and Difficulties Questionnaire subscales at each wave The proportion of siblings reported to have Emotional Symptoms in the ‘‘at risk’’ or ‘‘clinical’’ range increased across the waves (wave 1: 19.2%, wave 2: 15.5%, wave 3: 25.3%, and wave 4: 29.2%). The number of siblings in the at-risk or clinical range for Peer Problems also tended to increase (wave 1: 23.1%, wave 2: 23.8%, wave 3: 31.8%, wave 4: 28.2%). For Conduct Problems, marked problems were highest at wave 1 (52.4%), and then stayed consistent from waves 2–4 (wave 2: 27.7%, wave 3: 30.6%, wave 28.2%). Approximately one quarter of the sample had Hyperactive/Inattention symptoms in the at-risk or clinical range across the four waves (wave 1: 23.1%, wave 2: 24.8%, wave 3: 27.7%, wave 4: 24.3%). Finally, the proportion of siblings in the at-risk or clinical range dropped slightly over time for Prosocial Behaviour (wave 1: 20.2%, wave 2: 17.5%, wave 3: 17.1%, wave 4: 14.7%). 2.1.3. Comparisons between siblings of children with special health care needs and their same age peers on the Strengths and Difficulties Questionnaire subscales at each wave Comparisons between siblings of children with special health care needs and their peers participating in LSAC on each of the SDQ subscales were made, with and without controlling for socioeconomic position, using multivariate analyses of covariance (MANCOVA) at each wave. The multivariate results without controlling for SEP revealed significant differences between siblings of children with special health care needs and their peers at all ages; 4–5 years (Wilks D = 1.00, F(5, 4053) = 4.11, p = .001, multivariate h2 = .005), 6–7 years (Wilks D = 1.00, F(5, 3819) = 3.26, p = .006, multivariate h2 = .004), 8–9 years (Wilks D = 1.00, F(5, 3469) = 2.56, p = .026, multivariate h2 = .004), and 10–11 years (Wilks D = 1.00, F(5, 4028) = 3.92, p = .001, multivariate h2 = .005). The multivariate results were similar when controlling for SEP, except there were no significant differences between the groups at age 8–9 years. The results were as follows; 4–5 years (Wilks D = 99, F(5, 4044) = 3.06, p = .009, multivariate h2 = .004), 6–7 years (Wilks D = 99, F(5, 3810) = 2.72, p = .018, multivariate h2 = .004), and 10–11 years (Wilks D = 99, F(5, 4018) = 3.09, p = .009, multivariate h2 = .004). Table 3 displays the descriptive and univariate results for each of the subscales
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Table 3 Mean comparisons between siblings of children with special health care needs and their peers on the Strengths and Difficulties Questionnaire subscales at each wave while controlling for socioeconomic position using MANCOVA. Siblings of children with special health care needs (N = 104)
Same age peers without a brother or sister with a special health care need (N = 3810)
Univariate
M (SD)
M (SD)
F
p
(95% CI)
Wave 1: 4–5 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
2.11 2.92 4.04 1.80 7.26
(1.90) (2.30) (2.56) (1.72) (1.88)
1.65 2.42 3.43 1.60 7.76
(1.63) (2.00) (2.25) (1.52) (1.78)
6.99 5.27 5.91 0.93 7.32
.008 .022 .015 .334 .007
0.28 0.25 0.27 0.13 0.28
(0.09, 0.47) (0.06, 0.44) (0.08, 0.46) (0.06, 0.33) (0.47, 0.09)
Wave 2: 6–7 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
1.75 1.87 3.87 1.52 7.75
(1.66) (1.71) (2.76) (1.57) (1.92)
1.58 1.43 3.27 1.45 8.26
(1.70) (1.47) (2.03) (1.55) (1.68)
0.55 7.45 5.38 0.04 8.63
.457 .006 .020 .837 .003
0.10 0.30 0.29 0.05 0.30
(0.10, 0.30) (0.10, 0.49) (0.10, 0.49) (0.15, 0.24) (0.50, 0.11)
Wave 3: 8–9 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
1.99 1.66 3.95 1.84 7.95
(1.95) (1.79) (2.68) (1.93) (2.05)
1.56 1.29 3.15 1.43 8.26
(1.75) (1.44) (2.33) (1.61) (1.72)
4.02 3.92 7.65 3.93 2.30
.045 .048 .006 .048 .130
0.24 0.26 0.34 .25 0.38
(0.03, 0.46) (0.04, 0.47) (0.12, 0.56) (0.03–0.47) (0.60, 0.16)
Wave 4: 10–11 years Emotional symptoms Conduct problems Hyperactivity/inattention Peer problems Prosocial behaviour
2.35 1.81 3.91 1.89 8.01
(2.23) (1.82) (2.84) (2.18) (1.92)
1.91 1.33 3.17 1.49 8.52
(1.94) (1.47) (2.34) (1.71) (1.65)
4.37 9.04 8.43 4.44 9.38
.037 .003 .004 .035 .022
0.23 0.32 0.31 0.23 0.31
(0.03, 0.42) (0.13, 0.52) (0.12, 0.51) (0.04, 0.43) (0.50, 0.11)
Cohen’s d
accounting for SEP. Siblings of children with special health care needs had significantly higher emotional, conduct, hyperactivity and peer problems than their same age peers at most waves except for peer problems at wave 1 and 2 and emotional symptoms at wave 2. Siblings of children with special health care needs had significantly fewer prosocial behaviours than their peers at waves 1, 2 and 4. All these differences were associated with small effect sizes. 2.1.4. Latent growth models for siblings of children with special health care needs and their same age peers on each of the SDQ subscale scores across childhood Prior to conducting multiple group analyses to compare emotional and behavioural functioning trajectories of siblings of children special health care needs and their peers, a series of two-factor latent growth models for each of the SDQ subscale scores were conducted separately for each group. All models were estimated using robust maximum likelihood estimate to adjust the fit indices and parameter estimates to account for non-normality. The model fit statistics are presented in Table 4. All models were an acceptable fit to the data, except Conduct Problems for both groups. It is possible that the course of conduct problems is not linear across time as there was some evidence that conduct problems are high at 4–5 years, decrease slowly across childhood then increase again at 10–11 years. Additional waves of data may be required to reliably model conduct problems over early to late childhood. The multiple group analyses presented in Table 5 revealed that there were significant differences between the groups for all SDQ subscales except for emotional symptoms. The pattern of results was similar when adjustment for the influence of socioeconomic position was made. Fig. 1 shows the SDQ subscale trajectories (estimated means at each time point) for siblings of children with special health care needs and their peers participating in LSAC, and Table 6 presents the standardised parameters for the latent growth models. The means of the intercepts were positive and significantly different from zero for all SDQ subscales for both groups. The variances of the intercepts were also significant indicating individual differences in the levels of emotional and behavioural functioning at wave 1. The intercepts for both groups were similar across the subscales. The means of all slopes on the SDQ subscales were significant for the same aged peers without a brother or sister with a special health care needs. Specifically, the slopes were positive for emotional symptoms and prosocial behaviour indicating that, on average, scores on these measures increased at a rate of .19 and .63 points each wave, respectively (also see Fig. 1). The slopes for hyperactivity and peer problems were negative, decreasing at a rate of .16 and .10 points each wave, respectively. For siblings of children with a special health care need, the only significant slope was for prosocial behaviour, with scores increasing at a rate of .47 points each wave. The variances of the slopes were significant for all subscales for children without a brother or sister with a special health care need and only significant for emotional symptoms, peer
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Table 4 Latent growth model fit statistics for the latent growth models for siblings of children with special health care needs and their peers on each of the SDQ subscales.
x2 (df) Siblings of children with a special health care need (n = 104) Emotional symptoms 20.63 (5)** Conduct problems 60.65 (6)*** Hyperactivity 14.08 (5)* Peer problems 5.61 (5) Prosocial behaviour 14.14 (5)*
CFI
TLI
RMSEA (90% CI)
.88 .50 .94 .99 .93
.83 .50 .92 .99 .92
.17 .30 .13 .03 .13
(.07–.22) (.23–.37) (.05–.22) (.00–.14) (.05–.22)
.96 .78 .98 .98 .94
.07 .17 .06 .05 .08
(.06–.08) (.15–.18) (.05–.07) (.03–.06) (.07–.10)
Same age peers without a brother or sister with a special health care need (n = 3833) Emotional symptoms 93.66 (5)*** .96 Conduct problems 526.47 (5)*** .82 Hyperactivity 75.25 (5)*** .99 Peer problems 44.18 (5)*** .99 Prosocial behaviour 137.27 (5)*** .95
Table 5 Multiple group analyses results for the latent growth models on each of the SDQ subscales accounting for and not accounting for socioeconomic position.
Emotional symptoms Unconstrained Constrained Hyperactivity Unconstrained Constrained Peer problems Unconstrained Constrained
Not accounting for socioeconomic position
Accounting for socioeconomic position
x2 (df)
x2 (df)
x2diff (df)a
125.94 (10)*** 146.08 (22)***
13.53 (12)ns
134.73 (14)*** 148.56 (28)***
22.28 (14)ns
89.30 (10)*** 194.45 (22)***
103.53 (12)***
112.33 (14)*** 218.83 (28)***
61.10 (14)***
54.22 (10)*** 83.28 (22)***
Prosocial behaviour Unconstrained Constrained
x2diff (df)a
59.43 (14)*** 89.91 (28)***
32.44 (12)**
160.10 (10)*** 227.84 (22)***
32.99 (14)**
164.35 (14)*** 239.00 (28)***
80.47 (12)***
105.21 (14)***
** p < .01. *** p < .001. ns not significant.
Table 6 Parameter estimates of the latent growth models for siblings of children with special health care needs and their same age peers on each of the SDQ subscales adjusting for socioeconomic position. Intercept mean
Slope mean
Siblings of children with a special health care need Emotional symptoms 1.84 (SE = .19)*** .15 (SE = .09) Hyperactivity 4.01 (SE = .26)*** .01 (SE = .09) *** Peer problems 1.32 (SE = .16) .16 (SE = .14) Prosocial behaviour 7.35 (SE = .19)*** .23 (SE = .07)**
Intercept variance 1.61 4.82 0.88 2.90
(SE = .59)** (SE = .89)*** (SE = .08)*** (SE = .50)***
Slope variance .30 .22 .97 .25
Same age peers without a brother or sister with a special health care need Emotional Symptoms 1.60 (SE = .03)*** .07 (SE = .01)*** 1.31 (SE = .07)*** .15 Hyperactivity 3.44 (SE = .04)*** .08 (SE = .02)*** 3.11 (SE = .12)*** .25 *** *** *** Peer Problems 1.47 (SE = .04) .10 (SE = .03) 0.93 (SE = .01) 1.00 Prosocial Behaviour 7.85 (SE = .03)*** .23 (SE = .01)*** 1.68 (SE = .08)*** .13
Intercept–slope covariance
(SE = .12)* .07 (SE = .21) (SE = .16) .04 (SE = .32) (SE = .04)*** .002 (SE = .21) ** (SE = .09) .37 (SE = .15)** (SE = .02)*** (SE = .02)*** (SE = .01)*** (SE = .02)***
.04 .17 .14 .18
SEP ! intercept .50 .30 .34 .21
SEP ! slope
(SE = .18)*** .06 (SE = .09) (SE = .32) .01 (SE = .10) ** (SE = .12) .16 (SE = .13) (SE = .25)
