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Disentangling the complex relations among caregiver and adolescent responses to adolescent chronic pain
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PAIN 151 (2010) 680–686
www.elsevier.com/locate/pain
Disentangling the complex relations among caregiver and adolescent responses to adolescent chronic pain Kevin E. Vowles a,⇑, Lindsey L. Cohen b, Lance M. McCracken c, Christopher Eccleston c a
Interdisciplinary Musculoskeletal Pain Assessment and Community Treatment Service, Haywood Hospital, Stoke-on-Trent PCT & Primary Care Sciences Research Centre, Keele University, Stoke-on-Trent, UK b Department of Psychology, Georgia State University, Atlanta, GA, USA c Centre for Pain Research, School for Health, University of Bath & Centre for Pain Services, Royal National Hospital for Rheumatic Diseases NHS Foundation Trust, Bath, UK
a r t i c l e
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Article history: Received 5 October 2009 Received in revised form 4 June 2010 Accepted 20 August 2010
Keywords: Chronic pain Adolescents Caregivers Psychosocial
a b s t r a c t The social context surrounding chronic pain is important, particularly in the case of pain in adolescents, where caregivers can be a key influence on adolescent social and physical activities. In general, greater adolescent difficulties are related to greater caregiver difficulties, and vice versa, although the strength of these relations has not been consistent across studies. Further, existing analyses have not evaluated more complex multivariate models involving both direct and indirect relations among adolescents and caregivers. There is consequently a lack of clarity in this area. The present analyses represent an initial attempt at explicating more precisely how adolescent and caregiver behaviors in response to pain influence adolescent functioning. Initially, a hypothetical model was constructed that included caregiver pain management behaviors, as well as adolescent and caregiver psychosocial responses to pain. The adequacy of this model was first evaluated with Pearson correlations and then with structural equation modelling using data from 120 adolescent-caregiver dyads. After some modification of the model to allow for adequate fit with the data, findings indicated that caregiver variables were only indirectly related to adolescent functioning via adolescent psychosocial responses to pain. This indirect relation may explain previous inconsistency across studies. Perhaps more importantly, the model tested may allow for an improved understanding of the complex relations among adolescents and caregivers factors. Finally, the need to adequately understand caregiver experiences in response to adolescent pain is highlighted and calls for appropriate intervention in young people struggling with chronic pain are reinforced within these analyses. Ó 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
1. Introduction Research indicates that the behavior of individuals with chronic pain is fundamentally impacted by the behavior of those around him or her (see [22] for a review). This effect is not limited to observable behaviors alone, but also includes cognitive and emotional functioning (e.g., [3,21,32]). In short, data suggest that empirical descriptions and explanations regarding the experience of chronic pain are likely to be more complete when the social context around this experience is also taken into account. The social environment is particularly relevant in instances of adolescent chronic pain, where the role of family, parents, and parenting appears crucial in understanding the experience and consequences of pain for the young person. It is now clear that there are ⇑ Corresponding author. Address: Interdisciplinary Musculoskeletal Pain Assessment and Community Treatment Service, Haywood Hospital, High Lane, Burslem, Stoke-on-Trent, Staffordshire ST6 7AG, UK. Tel.: +44 (0)1782 673752. E-mail address: [email protected] (K.E. Vowles).
complex bidirectional relations among both adolescent and caregiver emotional and physical functioning in response to pain [6,8,15–20,29,31]. In general, these studies indicate that increases in adolescent distress and disability are often related to increases in caregiver difficulties and vice versa. In spite of the established relations among adolescent and caregiver functioning in this area, there are inconsistencies within this literature. Some studies report significant relations among measures of adolescent functioning and caregiver variables such as protective or maladaptive responses to pain and distress [5,14,28,30,38], whereas others report weaker, non-significant associations with similar variables [12,14]. It is not clear why these relations hold in some circumstances and not in others. There has been little investigation into multivariate models of adolescent and caregiver variables, which could allow for an improved understanding of these relations, as well as an assessment of indirect relations among the variables involved, which may in turn explain the differences in previous results (see [26,27] for extended discussions regarding the need to test more complex models).
0304-3959/$36.00 Ó 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.pain.2010.08.031
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The present investigation was intended to address these issues. First, a theoretical model was developed via a review of the extant literature with regard to how adolescent and caregiver factors interact with one another to influence adolescent functioning. In particular, parent and caregiver psychosocial responses to pain were deemed to be important influences, as was caregiver response to adolescent pain behavior. Relevant constructs were then specified, relations among them were discussed and hypothesized within the model, and specific measures of each were identified. Initially, patterns of correlations among the measures were examined to determine if relations were in expected directions. Finally, the fit of the theorized model to available data was evaluated and adjusted where deemed appropriate via structural equation modelling (SEM). 2. Methods 2.1. Participants Data were collected from 124 adolescent-caregiver dyads consecutively attending an interdisciplinary pain treatment service in southwest England between February 2005 and April 2009. These data have not been previously reported upon in any published work from our group. On average, adolescents were 15.2 years old (SD = 1.7) at the time of treatment onset. The majority were female (76.7%) and White European (92.2%). Most reported continued participation in education, including full- and part-time attendance at schools in the community (36.8% and 21.8%, respectively), as well as home and hospital schooling (19.5% and 3.4%, respectively). Only a minority (6.9%) were not receiving any education. The remaining adolescents (11.5%) reported having finished compulsory education, which typically occurs at the age of 16 in the UK. In spite of the large proportion who were receiving education in some form, there was evidence of disruption in attendance with an average of 1.8 days (SD = 1.3) per week of education missed due to pain. Average pain duration was 4.7 years (SD = 4.3). Pain diagnoses were varied and often of a general and non-specific nature (30.8%; e.g., pain syndrome; diffuse idiopathic pain syndrome; musculoskeletal pain) or only specified an area of pain (37.1%; e.g., back pain; abdominal pain). When specific diagnoses were present, the most frequent were complex regional pain syndrome (20.2%) and hypermobility (10.6%). The majority of caregivers were mothers (93.3%); the remainder were fathers (4.0%) and one was an aunt (0.8%). Responses for the remaining two individuals were missing (1.9%). Caregivers were 44.1 years old (SD = 6.9) on average. Most caregivers were working at least part-time (69.7%) or were a homemaker (17.9%). The remainder reported that they were a full-time carer for the adolescent (7.9%), unemployed (2.2%), or registered disabled (2.2%). A small proportion (13.7%) reported having chronic pain.
Fig. 1. Theoretical model describing relations among adolescent and caregiver factors.
willingness to engage in painful activities in order to pursue desired goals and values, or acceptance of chronic pain, is associated with increased functioning in both adolescents and adults with chronic pain (e.g., [23,24,40]). Alternatively, a process of appraising pain as threatening and uncontrollable, commonly referred to as catastrophizing, is associated with higher disability (e.g., [7,13,36]). We also assumed that parenting stress would be relevant, as this could promote the occurrence of avoidant behavior in caregivers [20,25]. No measure of caregiver acceptance was available for use within this dataset. Finally, as caregiver’s pain management responses in relation to children are relevant to the occurrence of adolescent pain behavior, this area was included in the model as well [35,37]. Historically, the focus has been on so-called solicitous caregiver responses, which are assumed to reinforce pain behavior in adolescents, and have been shown to increase the probability of additional pain behaviors and disability [28,39]. More recent work has also expanded to include other types of relevant caregiver responding, including those that are meant to protect the child from further pain, criticize or minimize the child’s pain behavior, and encourage the child to monitor symptoms and continue activity [5,35,37]. Within the model itself, three of the latent constructs, labelled adolescent psychological responses, caregiver psychological responses, and caregiver pain management behavior, were hypothesized to co-vary with one another and to directly relate to the model endpoint, labelled Adolescent Functioning. Latent constructs and specific relations among them are displayed in Fig. 1.
2.2. Model development 2.3. Measures By design, adolescent functioning in physical and social domains was deemed to be of primary interest. Therefore, adolescent functioning was designated the model endpoint (Fig. 1). In addition, given the relevance of both adolescent and caregiver psychosocial experiences in relation to chronic pain, each was also added to the model. We specifically wanted to include measures tapping into the quality of interaction with persistent pain in both adolescents and caregivers. This interaction can be considered to exist on an ‘‘approach” or ‘‘avoidance” continuum, which also includes psychological experiences that alter the probability of engaging in activities that bring an increase in pain. For example, a process of
Two or three measures were identified for each of the latent variables specified in Fig. 1. Measures were selected based on relevance to the construct, the available database, and psychometric properties as detailed in the following sections. 2.3.1. Adolescent daily functioning The physical and social functioning subscales of the Bath Adolescent Pain Questionnaire (BAPQ) [9] were used to quantify daily functioning in adolescents. Items of both the physical functioning subscale (e.g., ‘‘I walk normally.”) and social functioning subscale
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(e.g., ‘‘I go out to meet friends.”) are rated on a five-point ordinal scale employing a frequency dimension ranging from ‘‘Never” to ‘‘Always.” Both subscales have nine items; possible scores range from 0 to 36. Higher scores on the subscales indicate poorer function. Previous study of the BAPQ with adolescents seeking treatment for pain has demonstrated adequate internal consistency, temporal stability, and construct validity [9].
make such a fuss about it.”), and responses that reassure or distract the child from pain (Encourage/Monitor; possible score range: 0–24; e.g., ‘‘reassure your child that she is going to be okay.”). Previous evaluations of the ARCS have supported its internal consistency and established relations with measures of adolescent emotional functioning [5,30,35]. 3. Results
2.3.2. Adolescent psychosocial functioning Two measures were used to quantify adolescent psychosocial functioning. The first was the child version of the Pain Catastrophizing Scale (PCS-C; possible score range: 0–52) [7], which contains 13 items, each of which is rated on a five-point ordinal scale evaluating the intensity of catastrophic thinking ranging from ‘‘Not at all” to ‘‘Extremely” (e.g., ‘‘When I am in pain, I can’t stand it anymore.”). Evaluation of the PCS-C has demonstrated supportive evidence regarding reliability and validity [7]. Second, the 20 item Chronic Pain Acceptance Questionnaire – Adolescent version was used (CPAQ-A; possible score range: 0– 80) [23]. The CPAQ-A reflects two components of acceptance of chronic pain: activity engagement and pain willingness. Activity engagement includes degree of participation in regular daily activities in the presence of pain (e.g., ‘‘When my pain increases, I can still do things I have to do.”). Pain willingness includes relative absence of attempts to avoid or control pain (e.g., ‘‘Before I can make any real plans, I have to get some control over my pain.” – reverse keyed). Reliability and validity have been demonstrated in the form of adequate internal consistency and based on significant correlations with measures of emotional, physical, and social functioning in adolescents with chronic pain [23]. 2.3.3. Caregiver psychosocial functioning Caregiver psychosocial functioning was also quantified using two measures. The parent version of the Pain Catastrophizing Scale (PCS-P; possible score range: 0–52) [13] was used to evaluate the severity of caregiver catastrophizing in relation to adolescent pain. Items are rated on the same five-point ordinal scale as the PCS-C. Aside from slight wording changes to reflect that items were inquiring about caregiver thoughts with regard to the child’s pain, item content was identical to the PCS-C (e.g., ‘‘When my child is in pain, I can’t stand it anymore.”). Psychometric properties of the measure are adequate and are detailed by Goubert et al. [13]. Caregiver stress was assessed via the short form of the Parenting Stress Index (PSI; possible score range: 36–180) [1]. The PSI total score reflects overall caregiver distress (e.g., ‘‘I feel trapped by my responsibilities as a parent.”), parent–child problematic interactions (e.g., ‘‘My child is not able to do as much as I expected.”), and caregiver perceptions regarding difficulty in managing their child’s behavior (e.g., ‘‘I feel that my child is very moody and easily upset.”). Adequate reliability and validity have been demonstrated across caregivers of a wide variety of children experiencing health difficulties or behavioral problems [1]. Although originally developed for preadolescent children, it has been successfully used with caregivers of adolescents experiencing chronic pain, as well as other chronic conditions [10,33]. 2.3.4. Caregiver pain management responses The three subscales of the Adult Responses to Children’s Symptoms (ARCS) [35] were used to assess caregiver responses to pain. The ARCS items use a sentence stem, which is: ‘‘When your child has pain, how often do you . . . ?”, and are rated on a five-point ordinal scale of frequency, ranging from ‘‘Never” to ‘‘Always.” The three subscales include caregiver protectiveness (Protect; possible score range: 0–60; e.g., ‘‘let your child stay home from school.”), responses that minimize, discount, or criticize the child’s pain as excessive (Minimize; possible score range: 0–32; e.g., ‘‘tell your child not to
3.1. Data integrity and correlations Initial data checks indicated that two caregiver-child dyads and also two additional caregivers were missing more than 50% of responses on the questionnaire measures. These cases were excluded from future analysis. No other participants had any missing responses. Therefore, data analysis proceeded with 120 dyads. See Table 1 for descriptive information of the primary measures used in this study. Univariate and multivariate distributions were next examined. Inspection of Mahalanobis d2 values did not indicate any multivariate outliers among the sample. The multivariate distribution was found to be normal, with a Mardia’s coefficient of multivariate kurtosis of 0.48. There was no evidence of significant univariate skewness or kurtosis across any of the variables. Pearson correlations are located in Table 1. These analyses were intended to provide an initial and preliminary check on the model in order to determine if the pattern of relations among included measures was as expected. The overall pattern of results broadly provided support for the theoretical model presented in Fig. 1. First, the measures assigned to the same latent variable were significantly and at least moderately correlated with one another (absolute value range r = 0.23 for the adolescent daily functioning measures to 0.58 for the adolescent psychosocial functioning measures, all p’s < .05). Additional relations amongst measures were also present and were in expected directions, with the sole exception of the ARCS Encourage/Monitor scale, which was associated with more difficulties in adolescent physical functioning. 3.2. Evaluation of the measurement and structural model Consistent with contemporary guidelines, model fit was evaluated using several fit indices and assessing for convergence among findings [4,34]. First, the v2 statistic was evaluated as the initial indicator of model fit. Given that sample size is known to influence conventional statistical testing, model fit was also assessed by determining whether the v2 value was less than two times the model degrees of freedom (v2 df) [34]. Second, the root mean square error of approximation (RMSEA) with 90% confidence intervals was assessed. Guidelines suggest that values of less than 0.05 indicate close fit, less than 0.08 reasonable fit, and less than 0.10 mediocre fit [4]. Finally, additional fit indices were evaluated relative to published guidelines [2,4]. These included the goodness-offit index (GFI: close fit >0.95, good fit >0.90), adjusted GFI, which adjusted for degrees of freedom (AGFI; good fit >0.80), and comparative fit index (CFI; adequate fit >0.90). As our sample size was smaller than the 200 minimum suggested by some, but over the 10 participants per observed variables suggested by others (e.g., [4,34]), we elected to place relatively more emphasis on RMSEA and CFI to aid in the interpretation of model fit, as these indices are less prone to overestimation of goodness-of-fit in samples smaller than 200 [11]. Our initial evaluation of the model indicated only modest fit with the data (see Table 2). Fig. 2 displays standardized fit indices; italicized coefficient values indicate percent variance explained (i.e., r2), non-italicized coefficient values represent either standardized factor loadings in the case of paths or Pearson correlations in
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K.E. Vowles et al. / PAIN 151 (2010) 680–686 Table 1 Descriptive information and correlations for primary measures.
* ** ***
Measure
Mean (SD)
1
2
3
Adolescent measures 1. Catastrophizing 2. Acceptance 3. Social functioning 4. Physical functioning
29.6 32.6 18.2 18.6
(9.6) (11.0) (6.1) (6.7)
– .58*** .30*** .23*
– .51** .33**
–
Caregiver measures 5. Protect 6. Encourage/monitor 7. Minimize 8. Catastrophizing 9. Parenting stress
19.7 22.3 8.8 27.3 79.1
(7.0) (4.3) (3.3) (11.1) (21.6)
.06 .03 .04 .47*** .09
.07 .09 .15 .51** .08
.23* .16 .16 .01 .35** .17
5
6
7
8
9
– .44***
–
– .05 .28* .08 .28* .06
– .24* .32* .37** .47***
– .004 .03 .04
– .33** .30*
p < .05. p < .005. p < .001.
Table 2 Fit indices from the structural equation modelling analyses. Model Initial model Modified model Final model *
4
v2 (df) *
63.0 (21) 35.7 (17)* 24.56 (15)
v2 df RMSEA (90% CI)
GFI
AGFI
CFI
3.00 2.09 1.64
.902 .935 .953
.790 .862 .888
.800 .901 .949
.131 (.094–.169) .097 (.051–.141) .074 (.001–.125)
p < .05.
the case of covariances. Several areas for potential modification were highlighted within these results. First, within the evaluation of the measurement model, the Distract subscale of the ARCS did not appear to fit well with the latent variable of caregiver management of child pain, b = .09, p = .45. Second, within the overall structural model, the co-variance specified between adolescent psychosocial response and caregiver pain management of child pain was weak and non-significant, r = .13, p = .29. Finally, also within the overall structural model, the direct paths between (a) caregiver pain management behaviors and adolescent functioning and (b) caregiver psychosocial response and adolescent functioning were both non-significant, absolute value b < .32, p > 0.18 for both paths. The model was therefore altered. These changes were introduced and evaluated sequentially in separate models in the
following order: (1) removal of the ARCS Distract subscale, (2) removal of the non-significant co-variance, and finally (3) removal of the non-significant paths. After each alteration to the model, fit was again evaluated to determine if removal of the non-significant paths increased or decreased model fit. In each instance, model fit was improved providing support for model adjustment. The altered model was then evaluated for fit with the data. Fit indices are located in Table 2. Overall, the fit appeared adequate, although it could be improved. The statistical package suggested a number of possible modifications that would improve model fit. Two of these modifications indicated that model fit would be substantially improved by specifying a co-variance between the two sets of error terms. The first was between the Protect subscale of the ARCS and the Social Functioning subscale of the BAPQ. Given that the original ARCS publication [35] highlighted how the result of highly protective caregivers may be diminished opportunities for adolescent social interaction, we felt that the inclusion of this co-variance was theoretically justifiable. The second was between caregiver and adolescent frequency of catastrophic cognitions. It was felt that such a co-variance was also theoretically justifiable given that both were assessing the same construct in adolescents and their caregivers.
Fig. 2. Standardized coefficients for initial model.
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Results of the evaluation of the final model are displayed in Table 2. Fit indices indicated adequate fit with the data. Fig. 3 displays the final model as well as standardized coefficients. To aid with clarity within Fig. 3, covariances between the two pairs of error terms are not displayed. The co-variance between the error terms was .30, p < .05, for adolescent and caregiver catastrophizing and .26, p < .05, for adolescent social functioning and caregiver protective behaviors. 4. Discussion The number of studies examining young people with chronic pain and their caregivers is growing. Although these studies are fairly universal in their support for the role of psychosocial issues in adaptation to pain, there is a degree of discrepancy with regard to precise relations among caregiver and child indices. The primary purpose of the present study was to examine a multivariate model of the relation between parent and child variables and specifically test direct and indirect effects. A theoretical model was developed that included caregiver and adolescent psychosocial responses, as well as caregiver pain management behaviors. It was hypothesized that these latent constructs would co-vary with one another, as well as directly influence adolescent functioning. When adequate model fit was achieved with the data, the covariances between caregiver and adolescent variables were removed, with the sole exception of caregiver psychosocial responses, which co-varied with adolescent psychosocial responses. The only variable from the model directly related to adolescent functioning was composed of adolescent acceptance of chronic pain and catastrophic cognitions. Caregiver psychosocial responses and pain management behaviors co-varied as well. Statistics aside, the influence of caregiver variables on adolescent functioning was indirect and made its influence manifest through adolescent psychosocial responses. These results seem reasonable and realistic modifications of the model, as caregiver behaviors can have varied and changeable effects during adolescence, a period of time that is often seen as the cusp between childhood, when there is high dependence of caregivers, and adulthood, which is characterized by independence.
Perhaps the most significant strength of the present analysis is that a conceptual model regarding how adolescent and caregiver factors interact to influence adolescent social and physical functioning was devised and an initial test performed. If this model holds through future investigations, which perhaps make use of alternate observed variables for the latent constructs specified, then there are clear implications with regard to clinical applicability, treatment conceptualization, and treatment delivery. For example, in caregivers presenting with psychosocial difficulties of their own or in relation to their child’s pain, adequate intervention specific to the caregiver seems paramount. When deriving a theoretical model, we choose to make a distinction not only between caregiver and adolescent variables, but also between private psychological experiences (e.g., cognitions) and publicly observable behaviors in the form of daily functioning for adolescents and responses to children’s pain for caregivers. An alternate interpretation of the final model derived via SEM could indicate the latter distinction between these private and observable behaviors was unnecessary as there was only one statistical link between caregiver and adolescent variables, which was of a moderate magnitude. Conceptually, it seemed more useful clinically to separate these latent constructs into private and public behaviors as different areas of difficulty may warrant specific and distinct interventions. For example, in caregivers, difficulties may stem from personal responses occurring when faced with a child suffering from pain they view as permanent. These difficulties may make themselves manifest as catastrophic thinking or a lack of acceptance of the situation, amongst other possible indicators, and may warrant an intervention focused on caregiver responses to unchangeable and aversive thoughts and emotions related to the child’s pain. Alternatively, caregiver difficulties may occur as a result of a skills deficit in responding to children’s pain behavior appropriately such that more adaptive child responses are reinforced. A skills training approach would seem most appropriate in this latter situation. A third alternative would occur when these difficulties appear in tandem, which could warrant a combined approach. In addition, caregivers can be struggling with emotional issues unrelated to the young person’s pain and these may be having an impact on both
Fig. 3. Standardized coefficients for final model. Note that the paths between the pairs of the error terms are not displayed within the figure and are instead reported within the text.
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parties as well. Obviously, appropriate intervention for the caregivers themselves is needed in these situations. In children, on the other hand, it seems more likely that private and public behaviors will ‘‘move together” in a manner of speaking – in other words, they are likely to be highly correlated, as they were in the final SEM model in the present study (r = 0.87). Previous work from our group using a separate sample of adolescents with chronic pain has also indicated a similar finding, where adolescent difficulties across both physical and psychosocial domains varied primarily along a single continuum [37]. Given these findings, it seems likely that an adequate intervention for adolescents experiencing significant difficulties with chronic pain will include a mix of methods, including exposure, interventions to decrease the impact and function of problematic thoughts, feelings, and sensations, as well as skills training for areas where deficits are indicated. Examples of such a multifaceted approach include Eccleston et al. [10] and Wicksell et al. [40]. This approach, although plausible, remains speculative. We are at the very beginning of this line of investigation. Future study will have to test these hypotheses and whether the distinction between public and private behaviors adopted within the theoretical model developed and tested in the present analyses is a useful one. There are limitations to acknowledge. Our analyses were restricted to a single caregiver, who tended to be the mother. Although this is a common problem in this area, and in the area of caregiver research in general [26], we are not able to confidently discuss the role of fathers or other caregivers in adolescent chronic pain. Furthermore, it is likely that there are multiple important roles played by other family members, healthcare providers, and friends, as well as within the home environment itself. In addition, our analyses were limited to self-report measures all collected at the same point in time. It may be that shared method variance or relations among individual items between the different measures altered the pattern of findings. Ideally, these data would have been prospective in nature as well, with the functioning variables assessed at a later time point in time. In addition, this model was developed and tested using only a single sample of adolescents and caregivers that could have inflated indices of the model fit or affected the significance of individual paths and covariances. Furthermore, there are several other relevant variables that were not evaluated, including familial history of pain, disruptions in caregiver mood, and socioeconomic status. The collection of data from additional samples assessing additional variables would address this latter concern. Given these limitations, future studies may benefit particularly from the inclusion of caregivers beyond mothers, measures of observed physical, social, or scholastic functioning, and longitudinal designs. The statistical approach we adopted is also worthy of some comment. By its very nature, SEM requires that a directional model be specified; that directional specification can sometimes indicate that causal relations are being tested. The cross-sectional nature of the data collected does not allow for such causal conclusions and it seems likely that the unidirectional relations specified in the model are bidirectional in reality. Whereas this study is but one in a series investigating how caregiver and child responses to chronic pain relate to one another, it provides one explanation to previous inconsistencies in the literature and examines some of the relevant variables within a multivariate context. It may be that caregiver variables and adolescent functioning with pain are not always directly related and that future analyses in this area should include more complex statistical procedures to test indirect relations amongst these variables. Further, it is clear that caregivers themselves can suffer immensely as a result of chronic pain in their children (e.g., [19,20]), yet it is not as clear that they are offered adequate treatment. It may be that this is a next crucial stage in research in this area – it seems
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[26] Palermo TM, Chambers CT. Parent and family factors in pediatric chronic pain and disability: an integrative approach. Pain 2005;119:1–4. [27] Palermo TM, Eccleston C. Parents of children and adolescents with chronic pain. Pain 2009;146:15–7. [28] Peterson CC, Palermo TM. Parental reinforcement of recurrent pain: the moderating impact of child depression and anxiety on functional disability. J Pediatr Psychol 2004;29:331–41. [29] Scharff L, Langan N, Rotter N, Scott-Sutherland J, Schenck C, Tayor N, McDonald Nolan L, Masek B. Psychological, behavioral, and family characteristics of pediatric patients with chronic pain: a 1-year retrospective study and cluster analysis. Clin J Pain 2005;21:432–8. [30] Simons LE, Claar RL, Logan DL. Chronic pain in adolescence: parental responses, adolescent coping, and their impact on adolescent’s pain behaviors. J Pediatr Psychol 2008;33:894–904. [31] Sleed M, Eccleston C, Beecham J, Knapp M, Jordan A. The economic impact of chronic pain in adolescence: methodological considerations and a preliminary costs-of-illness study. Pain 2005;119:183–90. [32] Sullivan MJ, Thorn B, Haythornthwaite JA, Keefe F, Martin M, Bradley LA, Lefebvre JC. Theoretical perspectives on the relation between catastrophizing and pain. Clin J Pain 2001;17:52–64. [33] Thienemann M, Martin J, Cregger B, Thompson HB, Dyer-Friedman J. Manualdriven group cognitive-behavioral therapy for adolescents with obsessive-
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PAIN 151 (2010) 680–686
www.elsevier.com/locate/pain
Disentangling the complex relations among caregiver and adolescent responses to adolescent chronic pain Kevin E. Vowles a,⇑, Lindsey L. Cohen b, Lance M. McCracken c, Christopher Eccleston c a
Interdisciplinary Musculoskeletal Pain Assessment and Community Treatment Service, Haywood Hospital, Stoke-on-Trent PCT & Primary Care Sciences Research Centre, Keele University, Stoke-on-Trent, UK b Department of Psychology, Georgia State University, Atlanta, GA, USA c Centre for Pain Research, School for Health, University of Bath & Centre for Pain Services, Royal National Hospital for Rheumatic Diseases NHS Foundation Trust, Bath, UK
a r t i c l e
i n f o
Article history: Received 5 October 2009 Received in revised form 4 June 2010 Accepted 20 August 2010
Keywords: Chronic pain Adolescents Caregivers Psychosocial
a b s t r a c t The social context surrounding chronic pain is important, particularly in the case of pain in adolescents, where caregivers can be a key influence on adolescent social and physical activities. In general, greater adolescent difficulties are related to greater caregiver difficulties, and vice versa, although the strength of these relations has not been consistent across studies. Further, existing analyses have not evaluated more complex multivariate models involving both direct and indirect relations among adolescents and caregivers. There is consequently a lack of clarity in this area. The present analyses represent an initial attempt at explicating more precisely how adolescent and caregiver behaviors in response to pain influence adolescent functioning. Initially, a hypothetical model was constructed that included caregiver pain management behaviors, as well as adolescent and caregiver psychosocial responses to pain. The adequacy of this model was first evaluated with Pearson correlations and then with structural equation modelling using data from 120 adolescent-caregiver dyads. After some modification of the model to allow for adequate fit with the data, findings indicated that caregiver variables were only indirectly related to adolescent functioning via adolescent psychosocial responses to pain. This indirect relation may explain previous inconsistency across studies. Perhaps more importantly, the model tested may allow for an improved understanding of the complex relations among adolescents and caregivers factors. Finally, the need to adequately understand caregiver experiences in response to adolescent pain is highlighted and calls for appropriate intervention in young people struggling with chronic pain are reinforced within these analyses. Ó 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
1. Introduction Research indicates that the behavior of individuals with chronic pain is fundamentally impacted by the behavior of those around him or her (see [22] for a review). This effect is not limited to observable behaviors alone, but also includes cognitive and emotional functioning (e.g., [3,21,32]). In short, data suggest that empirical descriptions and explanations regarding the experience of chronic pain are likely to be more complete when the social context around this experience is also taken into account. The social environment is particularly relevant in instances of adolescent chronic pain, where the role of family, parents, and parenting appears crucial in understanding the experience and consequences of pain for the young person. It is now clear that there are ⇑ Corresponding author. Address: Interdisciplinary Musculoskeletal Pain Assessment and Community Treatment Service, Haywood Hospital, High Lane, Burslem, Stoke-on-Trent, Staffordshire ST6 7AG, UK. Tel.: +44 (0)1782 673752. E-mail address: [email protected] (K.E. Vowles).
complex bidirectional relations among both adolescent and caregiver emotional and physical functioning in response to pain [6,8,15–20,29,31]. In general, these studies indicate that increases in adolescent distress and disability are often related to increases in caregiver difficulties and vice versa. In spite of the established relations among adolescent and caregiver functioning in this area, there are inconsistencies within this literature. Some studies report significant relations among measures of adolescent functioning and caregiver variables such as protective or maladaptive responses to pain and distress [5,14,28,30,38], whereas others report weaker, non-significant associations with similar variables [12,14]. It is not clear why these relations hold in some circumstances and not in others. There has been little investigation into multivariate models of adolescent and caregiver variables, which could allow for an improved understanding of these relations, as well as an assessment of indirect relations among the variables involved, which may in turn explain the differences in previous results (see [26,27] for extended discussions regarding the need to test more complex models).
0304-3959/$36.00 Ó 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.pain.2010.08.031
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The present investigation was intended to address these issues. First, a theoretical model was developed via a review of the extant literature with regard to how adolescent and caregiver factors interact with one another to influence adolescent functioning. In particular, parent and caregiver psychosocial responses to pain were deemed to be important influences, as was caregiver response to adolescent pain behavior. Relevant constructs were then specified, relations among them were discussed and hypothesized within the model, and specific measures of each were identified. Initially, patterns of correlations among the measures were examined to determine if relations were in expected directions. Finally, the fit of the theorized model to available data was evaluated and adjusted where deemed appropriate via structural equation modelling (SEM). 2. Methods 2.1. Participants Data were collected from 124 adolescent-caregiver dyads consecutively attending an interdisciplinary pain treatment service in southwest England between February 2005 and April 2009. These data have not been previously reported upon in any published work from our group. On average, adolescents were 15.2 years old (SD = 1.7) at the time of treatment onset. The majority were female (76.7%) and White European (92.2%). Most reported continued participation in education, including full- and part-time attendance at schools in the community (36.8% and 21.8%, respectively), as well as home and hospital schooling (19.5% and 3.4%, respectively). Only a minority (6.9%) were not receiving any education. The remaining adolescents (11.5%) reported having finished compulsory education, which typically occurs at the age of 16 in the UK. In spite of the large proportion who were receiving education in some form, there was evidence of disruption in attendance with an average of 1.8 days (SD = 1.3) per week of education missed due to pain. Average pain duration was 4.7 years (SD = 4.3). Pain diagnoses were varied and often of a general and non-specific nature (30.8%; e.g., pain syndrome; diffuse idiopathic pain syndrome; musculoskeletal pain) or only specified an area of pain (37.1%; e.g., back pain; abdominal pain). When specific diagnoses were present, the most frequent were complex regional pain syndrome (20.2%) and hypermobility (10.6%). The majority of caregivers were mothers (93.3%); the remainder were fathers (4.0%) and one was an aunt (0.8%). Responses for the remaining two individuals were missing (1.9%). Caregivers were 44.1 years old (SD = 6.9) on average. Most caregivers were working at least part-time (69.7%) or were a homemaker (17.9%). The remainder reported that they were a full-time carer for the adolescent (7.9%), unemployed (2.2%), or registered disabled (2.2%). A small proportion (13.7%) reported having chronic pain.
Fig. 1. Theoretical model describing relations among adolescent and caregiver factors.
willingness to engage in painful activities in order to pursue desired goals and values, or acceptance of chronic pain, is associated with increased functioning in both adolescents and adults with chronic pain (e.g., [23,24,40]). Alternatively, a process of appraising pain as threatening and uncontrollable, commonly referred to as catastrophizing, is associated with higher disability (e.g., [7,13,36]). We also assumed that parenting stress would be relevant, as this could promote the occurrence of avoidant behavior in caregivers [20,25]. No measure of caregiver acceptance was available for use within this dataset. Finally, as caregiver’s pain management responses in relation to children are relevant to the occurrence of adolescent pain behavior, this area was included in the model as well [35,37]. Historically, the focus has been on so-called solicitous caregiver responses, which are assumed to reinforce pain behavior in adolescents, and have been shown to increase the probability of additional pain behaviors and disability [28,39]. More recent work has also expanded to include other types of relevant caregiver responding, including those that are meant to protect the child from further pain, criticize or minimize the child’s pain behavior, and encourage the child to monitor symptoms and continue activity [5,35,37]. Within the model itself, three of the latent constructs, labelled adolescent psychological responses, caregiver psychological responses, and caregiver pain management behavior, were hypothesized to co-vary with one another and to directly relate to the model endpoint, labelled Adolescent Functioning. Latent constructs and specific relations among them are displayed in Fig. 1.
2.2. Model development 2.3. Measures By design, adolescent functioning in physical and social domains was deemed to be of primary interest. Therefore, adolescent functioning was designated the model endpoint (Fig. 1). In addition, given the relevance of both adolescent and caregiver psychosocial experiences in relation to chronic pain, each was also added to the model. We specifically wanted to include measures tapping into the quality of interaction with persistent pain in both adolescents and caregivers. This interaction can be considered to exist on an ‘‘approach” or ‘‘avoidance” continuum, which also includes psychological experiences that alter the probability of engaging in activities that bring an increase in pain. For example, a process of
Two or three measures were identified for each of the latent variables specified in Fig. 1. Measures were selected based on relevance to the construct, the available database, and psychometric properties as detailed in the following sections. 2.3.1. Adolescent daily functioning The physical and social functioning subscales of the Bath Adolescent Pain Questionnaire (BAPQ) [9] were used to quantify daily functioning in adolescents. Items of both the physical functioning subscale (e.g., ‘‘I walk normally.”) and social functioning subscale
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(e.g., ‘‘I go out to meet friends.”) are rated on a five-point ordinal scale employing a frequency dimension ranging from ‘‘Never” to ‘‘Always.” Both subscales have nine items; possible scores range from 0 to 36. Higher scores on the subscales indicate poorer function. Previous study of the BAPQ with adolescents seeking treatment for pain has demonstrated adequate internal consistency, temporal stability, and construct validity [9].
make such a fuss about it.”), and responses that reassure or distract the child from pain (Encourage/Monitor; possible score range: 0–24; e.g., ‘‘reassure your child that she is going to be okay.”). Previous evaluations of the ARCS have supported its internal consistency and established relations with measures of adolescent emotional functioning [5,30,35]. 3. Results
2.3.2. Adolescent psychosocial functioning Two measures were used to quantify adolescent psychosocial functioning. The first was the child version of the Pain Catastrophizing Scale (PCS-C; possible score range: 0–52) [7], which contains 13 items, each of which is rated on a five-point ordinal scale evaluating the intensity of catastrophic thinking ranging from ‘‘Not at all” to ‘‘Extremely” (e.g., ‘‘When I am in pain, I can’t stand it anymore.”). Evaluation of the PCS-C has demonstrated supportive evidence regarding reliability and validity [7]. Second, the 20 item Chronic Pain Acceptance Questionnaire – Adolescent version was used (CPAQ-A; possible score range: 0– 80) [23]. The CPAQ-A reflects two components of acceptance of chronic pain: activity engagement and pain willingness. Activity engagement includes degree of participation in regular daily activities in the presence of pain (e.g., ‘‘When my pain increases, I can still do things I have to do.”). Pain willingness includes relative absence of attempts to avoid or control pain (e.g., ‘‘Before I can make any real plans, I have to get some control over my pain.” – reverse keyed). Reliability and validity have been demonstrated in the form of adequate internal consistency and based on significant correlations with measures of emotional, physical, and social functioning in adolescents with chronic pain [23]. 2.3.3. Caregiver psychosocial functioning Caregiver psychosocial functioning was also quantified using two measures. The parent version of the Pain Catastrophizing Scale (PCS-P; possible score range: 0–52) [13] was used to evaluate the severity of caregiver catastrophizing in relation to adolescent pain. Items are rated on the same five-point ordinal scale as the PCS-C. Aside from slight wording changes to reflect that items were inquiring about caregiver thoughts with regard to the child’s pain, item content was identical to the PCS-C (e.g., ‘‘When my child is in pain, I can’t stand it anymore.”). Psychometric properties of the measure are adequate and are detailed by Goubert et al. [13]. Caregiver stress was assessed via the short form of the Parenting Stress Index (PSI; possible score range: 36–180) [1]. The PSI total score reflects overall caregiver distress (e.g., ‘‘I feel trapped by my responsibilities as a parent.”), parent–child problematic interactions (e.g., ‘‘My child is not able to do as much as I expected.”), and caregiver perceptions regarding difficulty in managing their child’s behavior (e.g., ‘‘I feel that my child is very moody and easily upset.”). Adequate reliability and validity have been demonstrated across caregivers of a wide variety of children experiencing health difficulties or behavioral problems [1]. Although originally developed for preadolescent children, it has been successfully used with caregivers of adolescents experiencing chronic pain, as well as other chronic conditions [10,33]. 2.3.4. Caregiver pain management responses The three subscales of the Adult Responses to Children’s Symptoms (ARCS) [35] were used to assess caregiver responses to pain. The ARCS items use a sentence stem, which is: ‘‘When your child has pain, how often do you . . . ?”, and are rated on a five-point ordinal scale of frequency, ranging from ‘‘Never” to ‘‘Always.” The three subscales include caregiver protectiveness (Protect; possible score range: 0–60; e.g., ‘‘let your child stay home from school.”), responses that minimize, discount, or criticize the child’s pain as excessive (Minimize; possible score range: 0–32; e.g., ‘‘tell your child not to
3.1. Data integrity and correlations Initial data checks indicated that two caregiver-child dyads and also two additional caregivers were missing more than 50% of responses on the questionnaire measures. These cases were excluded from future analysis. No other participants had any missing responses. Therefore, data analysis proceeded with 120 dyads. See Table 1 for descriptive information of the primary measures used in this study. Univariate and multivariate distributions were next examined. Inspection of Mahalanobis d2 values did not indicate any multivariate outliers among the sample. The multivariate distribution was found to be normal, with a Mardia’s coefficient of multivariate kurtosis of 0.48. There was no evidence of significant univariate skewness or kurtosis across any of the variables. Pearson correlations are located in Table 1. These analyses were intended to provide an initial and preliminary check on the model in order to determine if the pattern of relations among included measures was as expected. The overall pattern of results broadly provided support for the theoretical model presented in Fig. 1. First, the measures assigned to the same latent variable were significantly and at least moderately correlated with one another (absolute value range r = 0.23 for the adolescent daily functioning measures to 0.58 for the adolescent psychosocial functioning measures, all p’s < .05). Additional relations amongst measures were also present and were in expected directions, with the sole exception of the ARCS Encourage/Monitor scale, which was associated with more difficulties in adolescent physical functioning. 3.2. Evaluation of the measurement and structural model Consistent with contemporary guidelines, model fit was evaluated using several fit indices and assessing for convergence among findings [4,34]. First, the v2 statistic was evaluated as the initial indicator of model fit. Given that sample size is known to influence conventional statistical testing, model fit was also assessed by determining whether the v2 value was less than two times the model degrees of freedom (v2 df) [34]. Second, the root mean square error of approximation (RMSEA) with 90% confidence intervals was assessed. Guidelines suggest that values of less than 0.05 indicate close fit, less than 0.08 reasonable fit, and less than 0.10 mediocre fit [4]. Finally, additional fit indices were evaluated relative to published guidelines [2,4]. These included the goodness-offit index (GFI: close fit >0.95, good fit >0.90), adjusted GFI, which adjusted for degrees of freedom (AGFI; good fit >0.80), and comparative fit index (CFI; adequate fit >0.90). As our sample size was smaller than the 200 minimum suggested by some, but over the 10 participants per observed variables suggested by others (e.g., [4,34]), we elected to place relatively more emphasis on RMSEA and CFI to aid in the interpretation of model fit, as these indices are less prone to overestimation of goodness-of-fit in samples smaller than 200 [11]. Our initial evaluation of the model indicated only modest fit with the data (see Table 2). Fig. 2 displays standardized fit indices; italicized coefficient values indicate percent variance explained (i.e., r2), non-italicized coefficient values represent either standardized factor loadings in the case of paths or Pearson correlations in
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K.E. Vowles et al. / PAIN 151 (2010) 680–686 Table 1 Descriptive information and correlations for primary measures.
* ** ***
Measure
Mean (SD)
1
2
3
Adolescent measures 1. Catastrophizing 2. Acceptance 3. Social functioning 4. Physical functioning
29.6 32.6 18.2 18.6
(9.6) (11.0) (6.1) (6.7)
– .58*** .30*** .23*
– .51** .33**
–
Caregiver measures 5. Protect 6. Encourage/monitor 7. Minimize 8. Catastrophizing 9. Parenting stress
19.7 22.3 8.8 27.3 79.1
(7.0) (4.3) (3.3) (11.1) (21.6)
.06 .03 .04 .47*** .09
.07 .09 .15 .51** .08
.23* .16 .16 .01 .35** .17
5
6
7
8
9
– .44***
–
– .05 .28* .08 .28* .06
– .24* .32* .37** .47***
– .004 .03 .04
– .33** .30*
p < .05. p < .005. p < .001.
Table 2 Fit indices from the structural equation modelling analyses. Model Initial model Modified model Final model *
4
v2 (df) *
63.0 (21) 35.7 (17)* 24.56 (15)
v2 df RMSEA (90% CI)
GFI
AGFI
CFI
3.00 2.09 1.64
.902 .935 .953
.790 .862 .888
.800 .901 .949
.131 (.094–.169) .097 (.051–.141) .074 (.001–.125)
p < .05.
the case of covariances. Several areas for potential modification were highlighted within these results. First, within the evaluation of the measurement model, the Distract subscale of the ARCS did not appear to fit well with the latent variable of caregiver management of child pain, b = .09, p = .45. Second, within the overall structural model, the co-variance specified between adolescent psychosocial response and caregiver pain management of child pain was weak and non-significant, r = .13, p = .29. Finally, also within the overall structural model, the direct paths between (a) caregiver pain management behaviors and adolescent functioning and (b) caregiver psychosocial response and adolescent functioning were both non-significant, absolute value b < .32, p > 0.18 for both paths. The model was therefore altered. These changes were introduced and evaluated sequentially in separate models in the
following order: (1) removal of the ARCS Distract subscale, (2) removal of the non-significant co-variance, and finally (3) removal of the non-significant paths. After each alteration to the model, fit was again evaluated to determine if removal of the non-significant paths increased or decreased model fit. In each instance, model fit was improved providing support for model adjustment. The altered model was then evaluated for fit with the data. Fit indices are located in Table 2. Overall, the fit appeared adequate, although it could be improved. The statistical package suggested a number of possible modifications that would improve model fit. Two of these modifications indicated that model fit would be substantially improved by specifying a co-variance between the two sets of error terms. The first was between the Protect subscale of the ARCS and the Social Functioning subscale of the BAPQ. Given that the original ARCS publication [35] highlighted how the result of highly protective caregivers may be diminished opportunities for adolescent social interaction, we felt that the inclusion of this co-variance was theoretically justifiable. The second was between caregiver and adolescent frequency of catastrophic cognitions. It was felt that such a co-variance was also theoretically justifiable given that both were assessing the same construct in adolescents and their caregivers.
Fig. 2. Standardized coefficients for initial model.
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Results of the evaluation of the final model are displayed in Table 2. Fit indices indicated adequate fit with the data. Fig. 3 displays the final model as well as standardized coefficients. To aid with clarity within Fig. 3, covariances between the two pairs of error terms are not displayed. The co-variance between the error terms was .30, p < .05, for adolescent and caregiver catastrophizing and .26, p < .05, for adolescent social functioning and caregiver protective behaviors. 4. Discussion The number of studies examining young people with chronic pain and their caregivers is growing. Although these studies are fairly universal in their support for the role of psychosocial issues in adaptation to pain, there is a degree of discrepancy with regard to precise relations among caregiver and child indices. The primary purpose of the present study was to examine a multivariate model of the relation between parent and child variables and specifically test direct and indirect effects. A theoretical model was developed that included caregiver and adolescent psychosocial responses, as well as caregiver pain management behaviors. It was hypothesized that these latent constructs would co-vary with one another, as well as directly influence adolescent functioning. When adequate model fit was achieved with the data, the covariances between caregiver and adolescent variables were removed, with the sole exception of caregiver psychosocial responses, which co-varied with adolescent psychosocial responses. The only variable from the model directly related to adolescent functioning was composed of adolescent acceptance of chronic pain and catastrophic cognitions. Caregiver psychosocial responses and pain management behaviors co-varied as well. Statistics aside, the influence of caregiver variables on adolescent functioning was indirect and made its influence manifest through adolescent psychosocial responses. These results seem reasonable and realistic modifications of the model, as caregiver behaviors can have varied and changeable effects during adolescence, a period of time that is often seen as the cusp between childhood, when there is high dependence of caregivers, and adulthood, which is characterized by independence.
Perhaps the most significant strength of the present analysis is that a conceptual model regarding how adolescent and caregiver factors interact to influence adolescent social and physical functioning was devised and an initial test performed. If this model holds through future investigations, which perhaps make use of alternate observed variables for the latent constructs specified, then there are clear implications with regard to clinical applicability, treatment conceptualization, and treatment delivery. For example, in caregivers presenting with psychosocial difficulties of their own or in relation to their child’s pain, adequate intervention specific to the caregiver seems paramount. When deriving a theoretical model, we choose to make a distinction not only between caregiver and adolescent variables, but also between private psychological experiences (e.g., cognitions) and publicly observable behaviors in the form of daily functioning for adolescents and responses to children’s pain for caregivers. An alternate interpretation of the final model derived via SEM could indicate the latter distinction between these private and observable behaviors was unnecessary as there was only one statistical link between caregiver and adolescent variables, which was of a moderate magnitude. Conceptually, it seemed more useful clinically to separate these latent constructs into private and public behaviors as different areas of difficulty may warrant specific and distinct interventions. For example, in caregivers, difficulties may stem from personal responses occurring when faced with a child suffering from pain they view as permanent. These difficulties may make themselves manifest as catastrophic thinking or a lack of acceptance of the situation, amongst other possible indicators, and may warrant an intervention focused on caregiver responses to unchangeable and aversive thoughts and emotions related to the child’s pain. Alternatively, caregiver difficulties may occur as a result of a skills deficit in responding to children’s pain behavior appropriately such that more adaptive child responses are reinforced. A skills training approach would seem most appropriate in this latter situation. A third alternative would occur when these difficulties appear in tandem, which could warrant a combined approach. In addition, caregivers can be struggling with emotional issues unrelated to the young person’s pain and these may be having an impact on both
Fig. 3. Standardized coefficients for final model. Note that the paths between the pairs of the error terms are not displayed within the figure and are instead reported within the text.
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parties as well. Obviously, appropriate intervention for the caregivers themselves is needed in these situations. In children, on the other hand, it seems more likely that private and public behaviors will ‘‘move together” in a manner of speaking – in other words, they are likely to be highly correlated, as they were in the final SEM model in the present study (r = 0.87). Previous work from our group using a separate sample of adolescents with chronic pain has also indicated a similar finding, where adolescent difficulties across both physical and psychosocial domains varied primarily along a single continuum [37]. Given these findings, it seems likely that an adequate intervention for adolescents experiencing significant difficulties with chronic pain will include a mix of methods, including exposure, interventions to decrease the impact and function of problematic thoughts, feelings, and sensations, as well as skills training for areas where deficits are indicated. Examples of such a multifaceted approach include Eccleston et al. [10] and Wicksell et al. [40]. This approach, although plausible, remains speculative. We are at the very beginning of this line of investigation. Future study will have to test these hypotheses and whether the distinction between public and private behaviors adopted within the theoretical model developed and tested in the present analyses is a useful one. There are limitations to acknowledge. Our analyses were restricted to a single caregiver, who tended to be the mother. Although this is a common problem in this area, and in the area of caregiver research in general [26], we are not able to confidently discuss the role of fathers or other caregivers in adolescent chronic pain. Furthermore, it is likely that there are multiple important roles played by other family members, healthcare providers, and friends, as well as within the home environment itself. In addition, our analyses were limited to self-report measures all collected at the same point in time. It may be that shared method variance or relations among individual items between the different measures altered the pattern of findings. Ideally, these data would have been prospective in nature as well, with the functioning variables assessed at a later time point in time. In addition, this model was developed and tested using only a single sample of adolescents and caregivers that could have inflated indices of the model fit or affected the significance of individual paths and covariances. Furthermore, there are several other relevant variables that were not evaluated, including familial history of pain, disruptions in caregiver mood, and socioeconomic status. The collection of data from additional samples assessing additional variables would address this latter concern. Given these limitations, future studies may benefit particularly from the inclusion of caregivers beyond mothers, measures of observed physical, social, or scholastic functioning, and longitudinal designs. The statistical approach we adopted is also worthy of some comment. By its very nature, SEM requires that a directional model be specified; that directional specification can sometimes indicate that causal relations are being tested. The cross-sectional nature of the data collected does not allow for such causal conclusions and it seems likely that the unidirectional relations specified in the model are bidirectional in reality. Whereas this study is but one in a series investigating how caregiver and child responses to chronic pain relate to one another, it provides one explanation to previous inconsistencies in the literature and examines some of the relevant variables within a multivariate context. It may be that caregiver variables and adolescent functioning with pain are not always directly related and that future analyses in this area should include more complex statistical procedures to test indirect relations amongst these variables. Further, it is clear that caregivers themselves can suffer immensely as a result of chronic pain in their children (e.g., [19,20]), yet it is not as clear that they are offered adequate treatment. It may be that this is a next crucial stage in research in this area – it seems
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