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A preliminary validation of the Swedish version of the Pain Catastrophizing Scale for Children (PCS-C) for children and adolescents with cancer

Authors Cederberg JT , Weineland S, Dahl J, Ljungman G

Received 18 October 2018

Accepted for publication 29 April 2019

Published 6 June 2019 Volume 2019:12 Pages 1803—1811

DOI https://doi.org/10.2147/JPR.S191378

Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Erica Wegrzyn



Jenny Thorsell Cederberg,1 Sandra Weineland,2,3 JoAnne Dahl,4 Gustaf Ljungman1

1Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden; 2Research and Development Center, Primary Health Care, Region Västra Götaland, Sweden; 3Department of Psychology, University of Gothenburg, Göteborg, Sweden; 4Department of Psychology, Uppsala University, Uppsala, Sweden

Objectives: Pain is reported as one of the most common and difficult symptoms for children and adolescents with cancer to cope with. Pain catastrophizing has been identified as a process clearly related to pain intensity and disability. The Pain Catastrophizing Scale for Children (PCS-C) has been validated in several languages and populations but remains to be validated in pediatric oncology. The aim of the study was to validate a Swedish version of the PCS-C for children and adolescents with cancer.
Methods: All children, 7–18 years of age, being treated for cancer in Sweden at the time of the study were invited to participate. Study material was sent out to the registered address. Internal consistency, test–retest reliability and convergent validity were calculated. Factor structure was examined using principal component analysis (PCA). Descriptive statistics were used to investigate background data and norm values.
Results: 61 children/adolescents were included in the analyses. The results did not support the original three-factor structure of the PCS-C, but rather suggested that a two-factor structure excluding item 8 best represented the data. The internal consistency of that solution was good (α=0.87), the test–rest reliability was excellent (ICC=0.75) and convergent validity was demonstrated (r=0.46). The mean (SD) for the PCS-C in the sample was 19.1 (9.2), without item 8. A statistically significant difference was shown between genders, where girls reported a higher level of pain catastrophizing than boys. No difference was found with regard to age.
Discussion: The Swedish version of the PCS-C is now preliminarily validated for children and adolescents with cancer, for whom gender- and age-specific norm values are now available. Questions remain regarding the optimal factor structure of the PCS-C.

Keywords: The Pain Catastrophizing Scale for Children, instrument validation, children, adolescents, cancer, pain

Introduction

It has become more and more apparent that pain and emotions are closely interconnected and that they influence each other neurophysiologically.1,2 This means that pain does not only cause psychological distress, but that psychological distress also, in fact, amplifies the nerve transmission of pain impulses.35 Brain-imaging studies have shown that positive emotions neurologically weaken pain impulses, while negative emotions strengthen them.6 If the pain is perceived as a threat, pain impulses are neurophysiologically amplified.7 The role of pain catastrophizing and how it affects the pain experience has been emphasized in pain research since the 1980s.8 Pain catastrophizing refers to the process where pain is interpreted as very threatful.9 It can be understood as the cognitive element of the fear10 and is associated with an inability to shift attention away from pain.11,12 Pain catastrophizing is associated with disability in both pain patients13-16 and the general population.17 In accordance with the reciprocity between pain and emotions, pain catastrophizing is further related to intensified pain.7,1824 The Pain Catastrophizing Scale (PCS)25 was developed in the 1990s and has been widely used and validated in many languages since.2636 It contains three subscales measuring different aspects of pain catastrophizing: rumination, magnification and helplessness. The rumination subscale contains items measuring ruminative thoughts, worry and an inability to inhibit pain-related thoughts. The magnification subscale reflects the intensification of the unpleasantness of pain and expectancy of negative outcomes. The helplessness subscale reflects an inability to deal with pain. The PCS has shown good internal consistency and temporal stability and correlates with measures of psychological distress, functional disability and pain intensity.21,22,25,37 The child version of the Pain Catastrophizing Scale, the PCS for children (PCS-C) was developed in 200338 and was shown to have the same three-factor structure as the original version, good-to-excellent internal consistency and predictive and concurrent validity. The PCS-C has since been validated in different languages and for different populations,3942 supporting its psychometric properties, yet showing different results with regard to factor structure. In two studies with community samples, by Solé et al42 and Parkerson et al,39 the three-factor model was supported. In two other studies with chronic pain samples, by Kröner-Herwig et als40 and Pielech et al,41 the results rather suggested a one-factor model. The results of the Parkerson study39 and the Pielech study41 further indicated that the scale might benefit from removing two items, yet different ones in the two studies. The Pielech study provided clinical reference points from a sample of children with chronic pain. Furthermore, the Kröner–Herwig study40 showed higher scores in girls than boys. Taken together, the PCS-C is a well-validated scale with good psychometric properties that yet would benefit from further validation, particularly in clinical populations. The factor structure deserves further investigation, including number of items, as well as reference points, preferably that are age and gender specific.

Pain in children is common due to different causes. Everyday pain in active play and sport is very common but usually not medically significant. Acute pain may be caused by illness, trauma or medical procedures. Recurrent pain, such as stomachaches, headaches or limb pain, are experienced occasionally to frequently by up to a third of children. Children may also suffer from chronic or disease-related pain.43 For children with cancer, pain is reported as one of the most common and burdensome symptoms throughout their cancer trajectory.44 The pain is most often caused by the disease itself, side effects of cancer treatment and/or medical procedures.45,46 Given the reciprocity between pain and emotions, pain management would benefit from a multimodal approach acknowledging its psychological mechanisms to a higher extent. This would likely improve pain management in general, and for children with cancer in particular. Furthermore, in order to optimize treatments, processes of change need to be investigated. For that purpose instruments measuring these processes of change are needed. The PCS-C is one such instrument. To be able to evaluate mechanisms of change in different treatments for different populations, validation of relevant instruments for the population at hand is important. For children with cancer, the pain may be interpreted as particularly threatful, and for whom pain catastrophizing may play an even more significant role. Validation of the PCS-C in the context of pediatric cancer is therefore of great importance.

Aim

The aim of the study was to validate the Swedish version of the Pain Catastrophizing Scale for Children (PCS-C) in a sample of children and adolescents with cancer, by examining its factor structure, internal consistency, test–retest reliability, convergent validity and norm values.

Methods

Design

The study was a psychometric validation study with a cross-sectional design.

Context

The study was part of a larger project for which the overall aim was to develop psychological interventions to help children with cancer to cope with the pain that is often associated with cancer and its treatment. In this larger project, scales for measuring psychological flexibility in relation to pain, often called pain acceptance, were developed for children with cancer (The Pain Flexibility Scale for Children (PFS-C)),47 and their parents (The Pain Flexibility Scale for Parents (PFS-P)).48 The PCS-C was used as a validation measure for the PFS-C.

Participants

All children, 7–18 years of age, who were being treated for cancer in Sweden at the time of the study, were invited to participate. Two hundred and thirty-three patients were identified by the Swedish Childhood Cancer Registry. The patient information supplied by the Swedish Childhood Cancer Registry contained name and surname, social security number, address, center where the child was treated, time since diagnosis and start of treatment. For one child, the patient data were insufficient and the child was excluded. The research nurses at the six pediatric oncology centers in Sweden were consulted to double-check that none of the children had gone into palliation or deceased after data withdrawal, in order to make sure that these children were not contacted. One child was recognized as having gone into palliation and was therefore excluded.

Data collection

Two hundred and thirty-one children were invited via e-mail at their registered addresses. The study material comprised information about the study, a questionnaire for background information, the test version of the scale under development (the PFS-C),47 evaluation questions, and two validation measures, of which the PCS-C was one. Three different versions of the patient information were used: one for children 7 to 12 years of age, one for adolescents 13 to 18 years of age and one for parents. The patient information specified that the study concerned pain. Background information included age, gender, type and date of diagnosis, date of end of treatment if applicable and current and average (over the last week) level of pain and discomfort of pain, rated on a Numerical Rating Scale (NRS) from 0=“No pain/discomfort at all” to 10=“Unbearably lot of pain/discomfort”.49 The children were offered to be included in a lottery of movie tickets for participating in the study. Consent was given through participation in the study. For children under the age of 15, written parental consent was also required. Upon no reply, a reminder was sent out 2 weeks after the first post. Upon participation, the test material was sent out again 1 month after reception of the first measurement for the purpose of test–retest analysis. All study material was coded. The code key was only accessible to one of the researchers. Three posts were returned by the Postal Service. Sixty-two children participated in the study of which 39 participated in both measurements and 23 participated at one measurement. One was excluded due to inadequate completion of the questionnaires. Ten children declined participation. One hundred and fifty-six children did not respond. The study was approved by the Regional Ethical Review Board in Uppsala, Sweden [Dnr 2014/375].

Measures

Apart from the scale of focus for validation, a measure for validation was used.

The Pain Catastrophizing Scale for Children (PCS-C)

The PCS-C measures catastrophizing thoughts in children and adolescents in pain.25,38 The scale consists of 13 statements beginning with the phrase “When I have pain, …”. The respondent rate their agreement with the statement on a 5-point Likert scale, the score range is 0–52 and higher scores indicate a higher level of catastrophizing. The rumination subscale contains the four following statements: “…, I want pain to go away”, “…, I can’t keep it out of my mind”, “…, I keep thinking about how much it hurts” and “…, I keep thinking about how much I want the pain to stop”. The magnification subscale contains the three statements “…, I am afraid that pain will get worse”, “…, I keep thinking of other painful events” and “…, I wonder whether something serious will happen”. The helplessness subscale contains the following six statements: “…, I worry all the time whether pain will end”, “…, I feel I can’t go on”, “…, it’s terrible and I think it’s never going to be better”, “…, it’s awful and I feel it takes over me”, “…, I can’t stand it anymore” and “…, there’s nothing I can do reduce pain”. Cronbach’s alpha has been shown to be α=0.81–0.90 and the scale has been shown to correlate with pain intensity, disability, anxiety sensitivity and pain coping and to predict pain and disability.3842 A Swedish version of the PCS-C was used.

Measure for validation

Due to the aim of the larger study, to develop a scale for measuring psychological flexibility in relation to pain in children with cancer, the Avoidance and Fusion Questionnaire for Youth (AFQ-Y) was used to assess convergent validity. The AFQ-Y measures psychological inflexibility in youths.50,51 Psychological inflexibility has been proposed as a trans-diagnostic factor52,53 and to constitute a generalized vulnerability for psychopathology.54 Interventions targeting psychological inflexibility in relation to pain, promoting the counter process acceptance instead, have been shown to predict increased pain tolerance and decreased pain intensity and discomfort of pain in experimentally induced pain.5559 A pilot study preliminarily evaluating an acceptance-based intervention for children with cancer experiencing acute pain has also shown reductions in pain intensity and discomfort of pain.60 Psychological inflexibility and pain catastrophizing have been shown to be related constructs.61 In the AFQ-Y, respondents rate their agreement with statements targeting experiential avoidance and cognitive fusion such as “The bad things I think about myself must be true” and ”I am afraid of my feelings”, on a 5-point Likert scale. A higher score indicates a higher level of psychological inflexibility. The AFQ-Y has demonstrated excellent internal consistency, temporal stability and convergent, discriminant and construct validity. The short version of eight items was used, AFQ-Y8, which correlates positively with child-reported anxiety, physical symptoms and problem behavior and negatively with general quality of life.50,51 The psychometric properties of the AFQ-Y8 were investigated and supported in the larger project to which the current study pertains and hence for the population at hand, children and adolescents with cancer.62 The score range of the AFQ-Y8 is 0–24.

Statistical analyses

All statistical analyses were performed in IBM SPSS Statistics, version 24.63 Principal component analysis (PCA) was used to investigate factor structure. The correlation matrix revealed a high proportion of correlation coefficients above 0.30, Bartlett’s test of sphericity was significant, and the Kaiser–Meyer–Olkin index (KMO) was 0.80, supporting the factorability of the data set. The Kaiser’s criterion and the scree plot were assessed to determine the number of factors to extract. Preliminary analyses indicated interdependence between the factors and oblique rotation was used. Cronbach’s alpha was calculated to assess internal consistency. The intraclass correlation coefficient (ICC) was calculated to assess test–retest reliability, which is the recommended method.64,65 A two-way random Model assessing the single measures value was used.66 A value <0.40 indicates poor inter-rater-agreement, between 0.40 and 0.59 fair, between 0.60 and 0.74 good and >0.75 excellent.67 Correlation with the AFQ-Y8 was performed to assess convergent validity. The data on both scales were normally distributed and Pearson correlation was used. Correlation coefficients were interpreted in accordance with the guidelines by Cohen,68 where r=0.10–0.29 small, 0.30–0.49 medium and 0.5–1.0 large. Descriptive statistics were used with regard to background data and to calculate norm values. Independent samples t-test was performed to compare the means between genders and age groups, respectively.

Results

Descriptives

Sixty-one children were included in the statistical analyses. The mean age of the participants was 12.7 years (SD=3.4), the age ranged from 7 to 18 years and 33 (54%) were boys and 28 (46%) girls. The diagnoses were leukemias (23), brain tumors (13) and solid tumors (25). The means (SDs) of the children’s current and average level of pain during the last week were 1.1 (1.6) and 1.4 (1.5), respectively. The means (SDs) of the children’s current and average level of discomfort during the last week were 1.0 (1.7) and 1.5 (2.0), respectively.

Factor analysis

The PCA revealed three factors with eigenvalues above 1, explaining 42.4%, 11.7% and 8.8% of the variance, respectively. The scree plot revealed a distinct break after the first and another more subtle break after the second factor. Hence, the results were ambiguous with regard to number of factors to retain. Inspecting the different rotation solutions, they yielded very similar results. In the three-factor solutions, factor 3 was comprised of only item 8, “When I have pain, I want pain to go away”. A factor with only one item would be far too unstable and a three-factor solution would hence not be appropriate according to the data set. The analyses were, therefore, run again forcing a two- and one-factor solution, respectively. Item 8 did not reach a factor loading of 0.4, which is recommended, in either of these solutions and its communality value was low (0.156 and 0.155, respectively). Item 8 was therefore removed from the analyses. Without item 8, the analyses revealed two factors with eigenvalues exceeding 1, accounting for 44.9% and 12.6% of the variance, respectively. The result from scree plot was somewhat ambiguous, with a distinct break after factor 1 and yet another clear break after factor 2. The different two-factor solutions yielded similar results, with one more dominant factor of eight–nine items and a second factor with three-four items. Item 3 loaded quite similarly on both factors; slightly stronger on factor 1 in the Oblimin solution and slightly stronger on factor 2 in the Promax solution. Communalities were all above 0.3 (lowest 0.460). In the one-factor solution, the factor loading for item 12 was low, 0.139. For the rest of the items, factor loadings ranged from 0.448 to 0.804. The communalities for three items (7,12 and 13) were low (0.019–0.233). Taken together, the results suggested that a 2-factor solution excluding item 8 best represented the data. The factor loadings for a two-factor solution were somewhat higher with the Promax rotation. Factors, items, factor loadings and communalities for this solution are presented in Table 1.

Table 1 Factors, items, factor loadings and communalities of a two-factor solution with Promax rotation for the PCS-C, with item 8 (“When I have pain, I want pain to go away”) excluded

Reliability and convergent validity

Internal consistency, test–retest correlation coefficients and correlation coefficients for the validation with the AFQ-Y, including and excluding item 8 respectively, are presented in Table 2. The internal consistency of the scale was good, the test–rest reliability was excellent and the correlation with the AFQ-Y8 was medium, regardless of inclusion or exclusion of item 8.

Table 2 Internal consistency, test–rest correlation coefficients and Pearson’s r correlation coefficients for validation with the AFQ-Y

Norm values

Mean values, standard deviations (SDs), standard errors (SEs), confidence intervals (CIs) for means, trimmed means and medians, score ranges and total (possible) ranges for the total scale and the subscales, excluding item 8, are presented in Table 3. Including item 8 the mean (SD) was 22.5 (9.5); SE 1.3; 95% CI for means (19.9–25.1); 5% trimmed mean 22.4; median 22.0; score range 4–45 and total range 0–52. With regard to gender, the mean (SD) for girls (n=25) was 22.3 (8.6) and for boys (n=29) 16.2 (8.9), a statistically significant difference (t (52)=2.54, p=0.01, two-tailed). With regards to age, the mean (SD) for children 7–12 years of age (n=23) was 19.5 (9.1) and for adolescents 13–18 years (n=31) 18.7 (9.4), a nonsignificant difference (t (52)=0.32, p=0.75, two-tailed). Both gender- and age-specific means were calculated excluding item 8.

Table 3 Mean, standard deviation (SD), standard error (SE), confidence interval (CI) for mean, trimmed mean, median, score range and total (possible) range for the PCS-C, excluding item 8

Discussion

The aim of the study was to validate a Swedish version of the PCS-C for children and adolescents with cancer reporting pain. The results of the current study did not support the original three-factor structure of the PCS-C, but suggested that a two-factor structure excluding item 8 best represented the data. Previous results regarding the factor structure of the PCS-C have been inconsistent. Two studies, by Solé et al42 and Parkerson et al,39 have supported the three-factor structure of the original version by Crombez et al.38 Two other studies, by Kröner-Herwig et al40 and Pielech et al,41 have previously found no support for the three-factor model even though a one-factor solution best represented the data in those studies. In the Pielech study,41 items 7 and 8 were found problematic due to floor/ceiling effects. Although the Solé study42 and the Parkerson study39 found support for the original factor structure, items 8 and 12 were found problematic due to low factor loadings in both of these studies, and Solé recommended exclusion of item 8. Hence, as to factor structure, the results of the current study are partly consistent with previous studies. With regard to the composition of the two factors of the current study, factor 1 consisted of all items, except item 8, of the rumination scale, one item of the magnification subscale and four items of the helplessness subscale. Factor 2 consisted of three items of the magnification subscale and one item of the helplessness subscale. Hence, the composition of the subscales is not consistent with the original version. The internal consistency, test–rest reliability and convergent validity were calculated both including and excluding item 8, for which both solutions showed good internal consistency, excellent test–rest reliability and a medium correlation with the validation measure indicating convergent validity. These results are in line with previous studies supporting the psychometric properties of the scale.3842 The mean (SD) for the PCS-C in the sample was 22.5 (9.5) including item 8. This is higher than the mean reported in Crombez et al38 and Parkerson et al39 studies for community samples (16.85–17.20), but lower than the mean reported in the Kröner-Herwig et al study40 for children and adolescents with recurrent headaches and chronic pain (26.44–33.35). The fact that the mean is higher than in community samples is expected. However, that the mean is lower in our sample compared to a sample of children and adolescents with recurrent headaches and chronic pain is somewhat surprising. One may assume that the levels of pain catastrophizing would be higher in a sample of children and adolescents with cancer given the nature of the disease. Clinical reference points were provided by Pielech et al,41 suggesting that a mean of 17.6 corresponds to a low level of catastrophizing, 21.8 of a moderate level and 25.6 of a high level. Hence, the current sample seems to report moderate levels of pain catastrophizing. This result may be explained by the low levels of current and average pain ratings (1.1 and 1.4, respectively) in our sample. (In the Kröner-Herwig et al study40 the pain ratings were relatively high, 4.54–6.18.) Given that exclusion of item 8 has been recommended by previous studies and the current one, it is important to note the number of items when comparing means between samples henceforth. A statistically significant difference was shown between genders, where girls reported a higher level of pain catastrophizing than boys. This is in line with the results of the Kröner-Herwig et al study,40 although Parkerson et al39 did not find any difference between genders. No difference was found with regard to age, which is in line with the results of the Parkerson study, although a trend was found between younger and older children in the Kröner-Herwig study (where the younger children reported higher levels of catastrophizing). Taken together, the results of the present study support the psychometric properties of the PCS-C and are mainly consistent with previous studies with regards to norm values.

All children, 7–18 years of age, who were being treated for cancer in Sweden at the time of the study were invited to participate in the study. Many respondents reported previous but not current pain. This may explain the low mean pain level. The fact that respondents could report pain retrospectively is a limitation of the study, which may have affected the reports of pain catastrophizing. Furthermore, there was no control question asking the respondent if he/she had any experience of pain during their cancer trajectory. This may have inferred that children or adolescents who had not experienced any pain participated in the study. Pain is, however, reported by children and adolescents with cancer as one of the most frequent adverse symptoms during their cancer trajectory44 and is likely to affect all children and adolescents with cancer, to some extent, at one time or another. In addition, the patient information specified that the study addressed children and adolescents with cancer and pain. The risk of including participants without pain experience is therefore considered small. Twenty-seven percent of the children participated in the study. Even though this response rate is realistic given the average proportion of participants in survey research nowadays and the difficult situation that these patients are in, this still limits the generalizability of the results of the study. Furthermore, the sample size is particularly low with regard to factor analysis, and the study should be seen as a preliminary validation of the PCS-C for the population. The participants were evenly distributed across the age span, showing that younger children participated in the same extent as older adolescents. A Swedish version of the PCS-C was used, which has been available and used frequently but has not been validated previously. In order to assess if and how this version differs from the original version in any cultural or linguistic aspect, it remains to be validated in equivalent samples as well.

Gender- and age-specific norm values for the PCS-C are now available for children and adolescents with cancer. Pain catastrophizing has been shown to predict pain and disability in pain and community samples. For children with cancer, the role of pain catastrophizing may be even more pronounced, given the implicit threat of the disease. Validated instruments and population-specific norm values in pediatric oncology enable identifying patients likely to benefit from therapeutic interventions as well as screening for patients at risk of developing more prolonged pain conditions, and hence the possibility to offer them preventive interventions. The psychometric properties of the PCS-C were supported. The factorial validity of the PCS-C does, however, deserve more investigation, including optimal number of items. Given the small sample of the study, the results should be seen as preliminary.

Acknowledgments

We would like to thank the Swedish Childhood Cancer Registry for identifying participants for our study. We would also like to thank the research nurses of the pediatric oncology centers in Sweden for your cooperation to ensure that no families with children who had gone into palliation or died were contacted. Lastly, we would like to thank our participants for taking the time to fill out the questionnaires. This work was supported by grants from the Swedish Childhood Cancer Foundation [PR2013-0058] and the Swedish Cancer Society [CAN2013/749].

Disclosure

Dr Jenny Thorsell Cederberg reports grants from Swedish Childhood Cancer Fund and grants from Swedish Cancer Society, outside the submitted work. The authors report no other conflicts of interest in this work.

References

1. Linton SJ. Understanding Pain for Better Clinical Practice: A Psychological Perspective. Edinburgh: Elsevier; 2005.

2. Linton SJ, Shaw WS. Impact of psychological factors in the experience of pain. Phys Ther. 2011;91(5):700–711. doi:10.2522/ptj.20100330

3. Wiech K, Ploner M, Tracey I. Neurocognitive aspects of pain perception. Trends Cogn Sci. 2008;12(8):306–313. doi:10.1016/j.tics.2008.05.005

4. Wiech K, Tracey I. The influence of negative emotions on pain: behavioral effects and neural mechanisms. Neuroimage. 2009;47(3):987–994. doi:10.1016/j.neuroimage.2009.05.059

5. Tracey I. Getting the pain you expect: mechanisms of placebo, nocebo and reappraisal effects in humans. Nat Med. 2010;16(11):1277–1283. doi:10.1038/nm.2229

6. Denk F, McMahon SB, Tracey I. Pain vulnerability: a neurobiological perspective. Nat Neurosci. 2014;17(2):192. doi:10.1038/nn.3628

7. Zale EL, Lange KL, Fields SA, Ditre JW. The relation between pain-related fear and disability: a meta-analysis. J Pain. 2013;14(10):1019–1030. doi:10.1016/j.jpain.2013.05.005

8. Chaves JF, Brown JM. Spontaneous cognitive strategies for the control of clinical pain and stress. J Behav Med. 1987;10(3):263–276.

9. Rosenstiel A, Keefe F. The use of coping strategies in chronic low back pain patients: relationships to patient characteristics and current adjustment. Pain. 1983;17(1):33–44.

10. Leeuw M, Goossens MEJB, Linton SJ, Crombez G, Boersma K, Vlaeyen JWS. The fear-avoidance model of musculoskeletal pain: current state of scientific evidence. J Behav Med. 2007;30(1):77–94. doi:10.1007/s10865-006-9085-0

11. Crombez G, Eccleston C, Baeyens F, Eelen P. When somatic information threatens, catastrophic thinking enhances attentional interference. Pain. 1998b;75(2):187–198. doi:10.1016/S0304-3959(97)00219-4

12. Crombez G, Eccleston C, Baeyens F, Eelen P. Attentional disruption is enhanced by the threat of pain. Behav Res Ther. 1998a;36(2):195–204. doi:10.1016/S0005-7967(97)10008-0

13. Turner JA, Jensen MP, Romano JM. Do beliefs, coping, and catastrophizing independently predict functioning in patients with chronic pain? Pain. 2000;85(1):115–125.

14. Turner JA, Jensen MP, Warms CA, Cardenas DD. Catastrophizing is associated with pain intensity, psychological distress, and pain-related disability among individuals with chronic pain after spinal cord injury. Pain. 2002;98(1):127–134.

15. Turner JA, Mancl L, Aaron LA. Pain-related catastrophizing: a daily process study. Pain. 2004;110(1):103–111. doi:10.1016/j.pain.2004.03.014

16. Severeijns R, Vlaeyen JWS, van Den Hout MA, Weber WEJ. Pain catastrophizing predicts pain intensity, disability, and psychological distress independent of the level of physical impairment. Clin J Pain. 2001;17(2):165–172.

17. Severeijns R, van Den Hout MA, Vlaeyen JWS. The causal status of pain catastrophizing: an experimental test with healthy participants. Eur J Pain. 2005;9(3):257–265. doi:10.1016/j.ejpain.2004.07.005

18. Peters ML, Vlaeyen JWS, Weber WEJ. The joint contribution of physical pathology, pain-related fear and catastrophizing to chronic back pain disability. Pain. 2005;113(1):45–50. doi:10.1016/j.pain.2004.09.033

19. Buer N, Linton SJ. Fear-avoidance beliefs and catastrophizing: occurrence and risk factor in back pain and ADL in the general population. Pain. 2002;99(3):485–491.

20. Haythornthwaite JA, Clark MR, Pappagallo M, Raja SN. Pain coping strategies play a role in the persistence of pain in post-herpetic neuralgia. Pain. 2003;106(3):453–460.

21. Vervoort T, Goubert L, Vandenbossche H, Van Aken S, Matthys D, Child’s CG. Parents’ catastrophizing about pain is associated with procedural fear in children: a study in children with diabetes and their mothers. Psychol Rep. 2011;109(3):879–895. doi:10.2466/07.15.16.21.PR0.109.6.879-895

22. Edwards RR, Cahalan C, Calahan C, Mensing G, Smith M, Haythornthwaite JA. Pain, catastrophizing, and depression in the rheumatic diseases. Nat Rev Rheumatol. 2011;7(4):216–224. doi:10.1038/nrrheum.2011.2

23. Khan RS, Ahmed K, Blakeway E, et al. Catastrophizing: a predictive factor for postoperative pain. Am J Surg. 2011;201(1):122–131. doi:10.1016/j.amjsurg.2010.02.007

24. Pinto PR, McIntyre T, Almeida A, Araújo-Soares V. The mediating role of pain catastrophizing in the relationship between presurgical anxiety and acute postsurgical pain after hysterectomy. Pain. 2012;153(1):218–226. doi:10.1016/j.pain.2011.10.020

25. Sullivan MJL, Bishop SR, Pivik J. The Pain catastrophizing scale: development and validation. Psychol Assessment. 1995;7(4):524–532. doi:10.1037/1040-3590.7.4.524

26. Meyer K, Sprott H, Mannion AF. Cross-cultural adaptation, reliability, and validity of the German version of the pain catastrophizing scale. J Psychosom Res. 2008;64(5):469–478. doi:10.1016/j.jpsychores.2007.12.004

27. Miró J, Nieto R, Huguet A. The catalan version of the pain catastrophizing scale: a useful instrument to assess catastrophic thinking in whiplash patients. J Pain. 2008;9(5):397–406. doi:10.1016/j.jpain.2007.12.004

28. Yap JC, Lau J, Chen PP, et al. Validation of the Chinese Pain Catastrophizing Scale (HK‐PCS) in patients with chronic pain. Pain Med. 2008;9(2):186–195. doi:10.1111/j.1526-4637.2007.00307.x

29. Fernandes L, Storheim K, Lochting I, Grotle M. Cross-cultural adaptation and validation of the Norwegian pain catastrophizing scale in patients with low back pain. BMC Musculoskel Dis. 2012;13(1):111. doi:10.1186/1471-2474-13-111

30. Sehn F, Chachamovich E, Vidor LP, et al. Cross‐cultural adaptation and validation of the brazilian portuguese version of the pain catastrophizing scale. Pain Med. 2012;13(11):1425–1435. doi:10.1111/j.1526-4637.2012.01492.x

31. Morris LD, Grimmer-Somers KA, Louw QA, Sullivan MJ. Cross-cultural adaptation and validation of the South African Pain Catastrophizing Scale (SA-PCS) among patients with fibromyalgia. Health Qual Life Out. 2012;10(1):137. doi:10.1186/1477-7525-10-137

32. Cho S, Kim H-Y, Lee J-H. Validation of the Korean version of the pain catastrophizing scale in patients with chronic non-cancer pain. Qual Life Res. 2013;22(7):1767–1772. doi:10.1007/s11136-012-0308-2

33. Mohd Din FH, Hoe VCW, Chan CK, Muslan MA. Cultural adaptation and psychometric assessment of pain catastrophizing scale among young healthy Malay-speaking adults in military settings. Qual Life Res. 2015;24(5):1275–1280. doi:10.1007/s11136-014-0850-1

34. İlçin N, Gürpınar B, Bayraktar D, et al. Cross-cultural adaptation and validation of the Turkish version of the pain catastrophizing scale among patients with ankylosing spondylitis. J Phys Ther Sci. 2016;28(1):298–303. doi:10.1589/jpts.28.298

35. Bansal D, Gudala K, Lavudiya S, Ghai B, Arora P. Translation, adaptation, and validation of Hindi version of the pain catastrophizing scale in patients with chronic low back pain for use in India. Pain Med. 2016;17(10):1848–1858. doi:10.1093/pm/pnv103

36. Huijer HA-S, Fares S, French DJ. The development and psychometric validation of an Arabic-language version of the pain catastrophizing scale. Pain Res Manag. 2017;2017:1–7. doi:10.1155/2017/1472792

37. Engel JM, Wilson S, Tran ST, Jensen MP, Ciol MA. Pain catastrophizing in youths with physical disabilities and chronic pain. J Ped Psychol. 2013;38(2):192–201. doi:10.1093/jpepsy/jss103

38. Crombez G, Bijttebier P, Eccleston C, et al. The child version of the pain catastrophizing scale (PSC-C): a preliminary validation. Pain. 2003;104(3):639–646.

39. Parkerson HA, Noel M, Pagé MG, Fuss S, Katz J, Asmundson GJG. Factorial validity of the English-language version of the pain catastrophizing scale–child version. J Pain. 2013;14(11):1383–1389. doi:10.1016/j.jpain.2013.06.004

40. Kröner-Herwig B, Maas J. The German Pain Catastrophizing Scale for Children (PCS-C) - psychometric analysis and evaluation of the construct. Psycho-Soc Med. 2013;10:Doc07. doi:10.3205/psm000097

41. Pielech M, Ryan M, Logan D, Kaczynski K, White MT, Simons LE. Pain catastrophizing in children with chronic pain and their parents: proposed clinical reference points and reexamination of the Pain Catastrophizing Scale measure. Pain. 2014;155(11):2360–2367. doi:10.1016/j.pain.2014.08.035

42. Solé E, Castarlenas E, Miró J. A Catalan adaptation and validation of the Pain Catastrophizing Scale for children. Psychol Assessment. 2016;28(6):e119-e126. doi:10.1037/pas0000243

43. Finley GA, Franck LS, Grunau RE, von Baeyer CL. Why children’s pain matters. Pain. 2005;13:4.

44. Twycross A, Parker R, Williams A, Cancer-Related Pain GF. Pain management: sources, prevalence, and the experiences of children and parents. J Ped Oncol Nurs. 2015;32(6):369–384. doi:10.1177/1043454214563751

45. International Association for the Study of Pain (IASP). 2008-2009 Global year against cancer pain. [IASP Web site]. Available from: http://www.iasp-pain.org/GlobalYear/CancerPain. Accessed October 5, 2018.

46. Ljungman G, Kreuger A, Gordh T, Berg T, Sörensen S, Rawal N. Treatment of pain in pediatric oncology: a Swedish nationwide survey. Pain. 1996;68:385–394.

47. Thorsell Cederberg J, Weineland Strandskov S, Dahl J, Children’s LG. adolescents’ relationship to pain during cancer treatment: a preliminary validation of the Pain Flexibility Scale for Children. J Pain Res. 2017;10:1171–1178. doi:10.2147/JPR.S137871

48. Thorsell Cederberg J, Weineland Strandskov S, Dahl J, Ljungman G. Parents’ relationship to pain during cancer treatment – a preliminary validation of the Pain Flexibility Scale for parents (PFS-P) of children with cancer. J Pain Res. 2017;10:507–514. doi:10.2147/JPR.S127019

49. Ferreira-Valente M, Pais-Ribeiro J, Jensen M. Validity of four pain intensity rating scales. Pain. 2011;152:2399–2404. doi:10.1016/j.pain.2011.07.005

50. Greco LA, Lambert W, Baer RA. Psychological inflexibility in childhood and adolescence: development and evaluation of the avoidance and fusion questionnaire for youth. Psychol Assessment. 2008;20(2):93–102. doi:10.1037/1040-3590.20.2.93

51. Livheim F, Tengström A, Bond FW, Andersson G, Dahl J, Rosendahl I. Psychometric properties of the avoidance and fusion questionnaire for youth: a psychological measure of psychological inflexibility in youth. J Contextual Behav Sci. 2016;5(2):103–110. doi:10.1016/j.jcbs.2016.04.001

52. Hayes SC, Strosahl K, Wilson KG, et al. Measuring experiential avoidance: a preliminary test of a working model. Psychol Rec. 2004;54(4):553. doi:10.1007/BF03395492

53. Spinhoven P, Drost J, de Rooij M, van Hemert AM, Penninx BW. A longitudinal study of experiential avoidance in emotional disorders. Behav Ther. 2014;45(6):840–850. doi:10.1016/j.beth.2014.07.001

54. Kashdan TB, Barrios V, Forsyth JP, Steger MF. Experiential avoidance as a generalized psychological vulnerability: comparisons with coping and emotion regulation strategies. Behav Res Ther. 2006;44(9):1301–1320. doi:10.1016/j.brat.2005.10.003

55. Zeidan F, Gordon N, Merchant J, Goolkasian P. The effects of brief mindfulness meditation training on experimentally induced pain. J Pain. 2010;11(3):199–209. doi:10.1016/j.jpain.2009.07.015

56. Zeidan F, Martucci K, Kraft R, Gordon N, McHaffie J, Coghill R. Brain mechanisms supporting the modulation of pain by mindfulness meditation. J Neurosci. 2011;31(14):5540–5548. doi:10.1523/JNEUROSCI.5791-10.2011

57. Brown C, Jones A. Meditation experience predicts less negative appraisal of pain: electrophysiological evidence for the involvement of anticipatory neural responses. Pain. 2011;150(3):428–438. doi:10.1016/j.pain.2010.04.017

58. Choi K, Rampp T, Saha F, Dobos G, Musial F. Pain modulation by meditation and electroacupuncture in experimental submaximum effort tourniquet technique (SETT). Explore. 2011;7(4):239–245. doi:10.1016/j.explore.2011.04.004

59. Forsyth L, Hayes LL. The effects of acceptance of thoughts, mindful awareness of breathing, and spontaneous coping on an experimentally induced pain task. Psychol Rec. 2014;64(3):447–455. doi:10.1007/s40732-014-0010-6

60. Thorsell Cederberg J, Dahl J, von Essen L, Ljungman G. An acceptance-based intervention for children and adolescents with cancer experiencing acute pain - a single-subject study. J Pain Res. 2017;10:2195–2203. doi:10.2147/JPR.S139087

61. Elvery N, Jensen MP, Ehde DM, Day MA. Pain catastrophizing, mindfulness, and pain acceptance: what’s the difference? Clin J Pain. 2017;33(6):485–495. doi:10.1097/AJP.0000000000000430

62. Thorsell Cederberg J, Weineland S, Dahl J, Ljungman G. A preliminary validation of the Swedish short version of the avoidance and fusion questionnaire for youth (AFQ-Y8) for children and adolescents with cancer. J Contextual Behav Sci. 2018;10:50–54.

63. SPSS Statistics [Computer Program]. Armonk: IBM Corporation; 2016.

64. Terwee CB, Bot SDM, de Boer MR, et al. Quality criteria were proposed for measurement properties of health status questionnaires. J Clin Epidemiol. 2007;60(1):34–42. doi:10.1016/j.jclinepi.2006.03.012

65. Weir JP. Quantifying test-retest reliability using the Intraclass correlation coefficient and the SEM. J Strength Cond Res. 2005;19(1):231–240. doi:10.1519/15184.1

66. Landers R Computing Intraclass Correlations (ICC) as estimates of interrater reliability in SPSS. [The Winnower web site]. Available from: https://thewinnower.com/papers/1113-computing-intraclass-correlations-icc-as-estimates-of-interrater-reliability-in-spss. Accessed October 5, 2018.

67. Cicchetti DV. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol Assessment. 1994;6(4):284–290. doi:10.1037/1040-3590.6.4.284

68. Cohen J. Statistical Power Analysis for the Behavioral Sciences. Vol. 2. Hillsdale: L. Erlbaum Associates; 1988.

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