ORIGINAL ARTICLE
Pain referents used to respond to the Pain Catastrophizing Scale S. Kapoor1, B.E. Thorn1, O. Bandy1, K.L. Clements2 1 Psychology Department, The University of Alabama, Tuscaloosa, USA 2 Department of Behavior and Mental Health, Birmingham Veterans Affairs Medical Center, Birmingham, USA
Correspondence Beverly E. Thorn E-mail: [email protected]; [email protected] Funding sources None. Conflicts of interest None declared. Accepted for publication 27 May 2014 doi:10.1002/ejp.561
Abstract Background: Pain catastrophizing has emerged as a highly important construct in pain research. The Pain Catastrophizing Scale (PCS) is a widely used self-report measure used to determine a person’s level of pain catastrophizing, assumed to be associated with an ongoing, recalled or anticipated pain experience. In practice, instructions for self-reporting catastrophizing typically do not provide a specific pain referent, even when assessing patients with chronic pain. Researchers have noted that it is not known what type of pain participants are referring to when responding to a catastrophizing questionnaire. Method: In the current study, 182 presumably healthy undergraduate students completed the PCS followed by a query regarding the pain referent used to complete the scale. In addition, they were asked if they have ever experienced chronic pain and to list their worst pain experience. Results: The most commonly used primary referents included pain due to acute injury (26.4%), headache (18.0%) and general physical pain (11.5%). The type of primary referent and the number of referents did not influence the catastrophizing scores. However, the catastrophizing scores were influenced by the context of the primary pain referent, i.e., whether the primary pain referent was non-chronic worst pain, both chronic and worst pain, chronic pain or unrelated to either chronic or worst pain. Notably, a larger than expected proportion of participants reported having experienced chronic pain (44.5%; n = 81). Conclusion: The examination of pain referents while responding to a catastrophizing measure would add to our understanding of a person’s pain experience and related catastrophic cognitions.
1. Introduction Pain catastrophizing involves exaggerated maladaptive cognitions or emotions in response to ongoing, anticipated or recalled pain (Sullivan et al., 2001; Quartana et al., 2009). This concept is continuously evolving, and as such, this is one of the several definitions of catastrophizing. The detrimental role of catastrophizing in managing and coping with pain is well documented and catastrophizing is widely acknowledged as an important predictor of pain experience (Campbell et al., 2010a,b; Khan et al., 2011; Mankovsky et al., 400 Eur J Pain 19 (2015) 400--407
2012). Findings are consistent across different study populations, including people with chronic pain as well as individuals experiencing acute or experimental pain (Citero et al., 2007; Edwards et al., 2011; de Boer et al., 2012). Increasingly, the role of situation-specific catastrophizing as compared to dispositional catastrophizing is being examined (Dixon et al., 2004; Campbell et al., 2010a,b; Sturgeon and Zautra, 2012). Catastrophizing measured in the absence of a specific pain referent, sometimes also referred to as trait catastrophizing, is believed to be a dispositional characteristic. On the © 2014 European Pain Federation - EFICâ
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What’s already known about this topic? • Robust empirical evidence that adverse clinical outcomes are associated with pain catastrophizing. • Increasing recognition for the need to comprehensively understand a person’s pain-related catastrophic thoughts. What does this study add? • This study evaluates pain referents used by respondents while completing a dispositional catastrophizing measure. • The study corroborates the importance of the context of the referents and their association with catastrophizing levels.
other hand, catastrophizing measured during a painful experience or immediately following a pain experience is considered situation-specific (Edwards et al., 2005; Campbell et al., 2010a,b). The standard instructions are commonly based upon the assumption that individuals with chronic pain will refer to their chronic pain when responding to the catastrophizing questions, whereas non-clinical study participants will refer to a recalled pain experience; thus, the responses may vary greatly (Ruscheweyh et al., 2011). It has been suggested that not taking into account the pain referent participants used, potentially makes obtained scores difficult to interpret (Campbell et al., 2010a,b). It has been proposed that catastrophizing may represent a latent construct that requires activation via a pain cue, possibly a painful stimulus or a cued recall of a specific pain experience (Beck et al., 1979; Edwards et al., 2008). It is logical to expect that the level of self-reported catastrophizing would depend upon the pain cue, present or recalled. Thus, it is important to inquire and examine the pain referents used when completing a self-report measure of catastrophizing. In the present study, presumably healthy undergraduates in Introductory Psychology classes completed the Pain Catastrophizing Scale (PCS) along with other measures assessing pain-related catastrophic thoughts. The PCS is a widely used, validated 13-item scale with respondents asked to endorse items related to catastrophic pain-related thoughts (Sullivan et al., 1995). Participants did not receive experimentally induced pain, nor were they given any specific instructions for completing the PCS beyond the standard (dispositional) instructions. The latter did not include a specific pain cue as is typically provided in the standard PCS instructions (see Measures section). The foremost © 2014 European Pain Federation - EFICâ
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Table 1 Context of primary pain referents. Terms used in the manuscript Unrelated Non-chronic + worst Chronic + worst
Chronic
Description Pain referent unrelated to either the self-reported chronic or worst pain Pain referent which was self-reported as the worst pain ever experienced, but not chronic Pain referent which was self-reported as both chronic pain as well as the worst pain ever experienced Pain referent which was experienced chronically but was not described as the worst pain experienced
aim of the study was to assess the referents used by the respondents while responding to the PCS. In addition, the association of catastrophizing scores with the type of pain, number and context of the primary referents was examined. Context of the primary pain referent indicates whether the primary pain referent was nonchronic worst pain, both chronic and worst pain, chronic pain or unrelated to either chronic or worst pain (see Table 1).
2. Methods 2.1 Participants Participants in this study included 182 undergraduate students enrolled in Introductory Psychology classes. They received credit towards course research requirements in exchange for completion of the study. The age of the participants was between 17 and 34 years (M = 19.42; SD = 1.82), and 74.0% (n = 136) of the participants were female.
2.2 Procedure The participants were recruited from the Introductory Psychology classes through the university’s Psychology Subject Pool. All the participants who chose to participate were consented prior to their participation in accordance with the Institutional Review Board (IRB) guidelines. There were no specific exclusion or inclusion criteria. Once the participants were consented, each was individually administered the PCS, a brief pain questionnaire and a demographics survey. Other pain-related measures were also administered, which are not a part of the present study. The study was approved by the university’s IRB.
2.3 Measures 2.3.1 Demographics and pain catastrophizing Demographic information pertaining to the age and gender of the participants was collected. The PCS was used to
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measure pain catastrophizing. PCS is a validated 13-item scale examining catastrophizing (Sullivan et al., 1995). This measure requires participants to rate on a 5-point scale from 0 (not at all) to 4 (all the time) how often they experience specific catastrophic thoughts or feelings when in pain. It measures catastrophizing on three dimensions, namely magnification, rumination and helplessness, and the total score for catastrophizing is the sum of the raw scores. The final score is obtained by adding the raw scores on each item. The possible score range was from 0 to 52, with higher scores indicating greater catastrophic thinking. Generic instructions given to participants were as follows: ‘Please write the number that best describes how much each item listed is similar to a thought or feeling you have when you experience physical pain. Before beginning, please reflect on a time when you have experienced physical pain.’
2.3.2 Pain referents A brief pain survey was used to assess the pain referents used by the participants. In this survey, participants were asked to list the type (or types) of pain they were referencing when completing the PCS. The participants could list multiple referents. However, for the present study, the first referent listed was considered the primary referent, and as such, it was included in the analyses. Participants were next asked if they had ever experienced chronic pain (either chronic or intermittent). If participants responded positively to either, they were asked to describe the type of pain they had experienced. The final question asked the participants to list their worst pain experience and its duration.
2.4 Data analyses Descriptive statistics are either reported as means and standard deviations [M (SD)] or frequency and percentages [n (%)], unless otherwise noted. The primary pain referents used by the participants were assigned to content categories by the researchers. Following the initial coding/categorization of all responses (coder A), the primary pain referents were categorized by two other independent coders (coders B and C). This was accomplished by giving both coders the putative categories, the verbatim responses and instructions to either match the response to the provided categories or suggest other categories if there was not a match. Cohen’s kappa was calculated to determine the inter-rater reliability for the categorization of pain referents between coder A and each of the other coders individually. Once the categories of the primary referents were established, the next step of the data analyses was conducted. Frequency statistics are reported for the type of referents used, the number of referents used and the context of the referents used by the participants. When more than one pain referent was listed by the participant, the first referent listed was considered the primary referent and was used in subsequent analyses. For the purpose of examining the context of the primary pain referent, the participants were divided into 402 Eur J Pain 19 (2015) 400--407
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four groups: participants who used a primary pain referent unrelated to or different from either the worst or chronic pain listed (referred to as unrelated); participants using their worst pain as the primary referent (i.e., the primary referent was not their chronic pain experience, referred to as the non-chronic + worst); participants using their chronic pain as the primary referent (which was not described as their worst pain; referred to as chronic); and lastly, participants using their chronic pain as the primary referent which was also reported as their worst pain (referred to as chronic + worst) (see Table 1). Three one-way analyses of variance (ANOVAs) were conducted to examine whether there were any differences in the catastrophizing scores based upon the type of primary referent, the number of referents used and the context of the primary referent used (see Table 2). As an exploratory final step of the analyses, the age, sex, catastrophizing scores and primary referents used by the participants who endorsed having experienced chronic pain were compared with those who did not (see Table 3).
3. Results 3.1 Primary pain referents The initial generation of categories for the primary referents was performed by two of the authors; B.E.T. (principal investigator and corresponding author) and O.B. (co-author) independently came up with categories based upon their interpretations of the most common responses. Consultation to resolve discrepancies resulted in the final categories. Three coders then coded (B.E.T., O.B. and S.K.) all the responses into those categories independently. Ten distinct categories of pain types were created based upon the location and source of pain. These included pain due to acute injury, abdominal pain, headache, menstrual pain, emotional pain, post-surgical pain, back pain, general physical pain, dental pain and others. The category ‘other’ included referents that were used less than two times by participants, such as ear pain, throat pain and pain due to infections. The category of emotional pain included descriptors self-reported by the participants such as, ‘emotional pain’, ‘mental pain’, ‘pain of losing loved ones’, ‘pain of break-up of relationships’ and ‘loneliness’. The inter-rater reliability between coders A and B was κ = 0.984, the reliability between coders A and C was κ =0.846, and between coders B and C was κ = 0.881. The most common types of primary referents were pain due to acute injury (26.4%), headache (18.0%), general physical pain (11.5%) and menstrual pain (10.9%). The number of referents used by the participants ranged from 1 to 4, with the largest percentage of participants reporting a single pain referent (59.3%) and smallest percentage (2.8%) © 2014 European Pain Federation - EFICâ
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Table 2 One-way analyses of variance (ANOVAs) examining differences in the PCS scores based upon the type of primary pain referents, number of referents listed and context of the primary pain referent used by the participants.
n Type of primary referent Acute injury Headache General physical Menstrual Others Back pain Post-surgical Dental pain Emotional Abdominal pain Number of referents listed 1 2 3 4 Context of primary referents Unrelated Non-chronic + worst Chronic + worst Chronic
Overall sample
Comparisons
M
SD
48 (26.4%) 33 (18.0%) 21 (11.5%) 20 (10.9%) 20 (10.9%) 10 (5.5%) 9 (4.9%) 8 (4.4%) 7 (3.8%) 6 (3.3%)
8.93 12.44 10.13 14.08 13.72 12.16 14.40 12.20 12.46 14.13
5.35 7.48 6.41 6.71 7.00 5.86 7.75 6.35 5.71 8.57
108 (59.34%) 55 (30.22%) 14 (7.69%) 5 (2.75%)
12.18 11.29 10.29 9.76
6.67 6.17 9.28 6.70
63 (34.62%) 72 (39.56%) 30 (16.48%) 17 (9.34%)
10.63 11.13 14.59 12.94
6.51 7.11 6.04 5.44
n (%)
182
182
182
F
df
p
η2
1.92
9172
0.052
0.009
0.597
3178
0.618
0.010
2.846
3178
0.039
0.046
N, number of participants; M, mean PCS scores; SD, standard deviations of PCS scores; df, degrees of freedom; η2, eta-squared value for effect size; Unrelated, pain referent unrelated to either the self-reported chronic or worst pain; Non-chronic + worst, worst pain experience used by the participant as a primary referent which was not experienced chronically; Chronic + worst, primary pain referent used by the participant which was self-reported as both chronic pain and worst pain experience; Chronic, self-reported chronic pain experience which was not the worst pain experience and reported as a primary referent.
reporting four pain referents. Further analyses of the context of the primary pain referents of the participants indicated that overall, 39.6% primarily referred to their worst pain experience which was not experienced chronically (non-chronic + worst), 34.6% referred to a pain unrelated to either chronic pain or worst pain (unrelated), 16.5% referred to their chronic pain also described as their worst pain experience (chronic + worst), whereas 9.3% referred to their chronic which was not described as their worst pain (chronic) (see Table 2 for more details).
3.2 Relationship between catastrophizing and primary pain referents The mean PCS score was 11.70 (SD = 6.70) for the overall sample. The ANOVA results indicated that the PCS scores did not vary based upon the number of pain referents listed by the participants [F(3178) = 0.60; p = 0.62; η2 = .01]. For the type of primary pain referent used by participants, the overall difference in PCS scores fell just short of standard levels of statistical significance [F(9172) = 1.92; © 2014 European Pain Federation - EFICâ
p = 0.052; η2 = 0.009]. Follow-up Tukey’s post-hoc tests confirmed that none of the group differences were significant. As the concept of emotional pain and its distinction from physical pain is not very well understood, further analyses were conducted after excluding emotional pain. In addition, the ‘other’ group included a heterogeneous group of pain referents and was also excluded in this secondary exploration. The results were similar [F(7147) = 1.68; p = 0.057; n = 155] (see Table 2). On the contrary, a one-way ANOVA indicated that there was a significant difference between the PCS scores based upon the context of the primary referents [F(3178) = 2.846; p = 0.039; η2 = 0.046]. Least significant difference post-hoc comparisons revealed that chronic + worst pain referent group had significantly higher catastrophizing scores (M = 14.59; SD = 6.04; n = 30) than the non-chronic + worst pain group (M = 11.13; SD = 7.11; n = 72) and the unrelated group (M = 10.63; SD = 6.51; n = 63). The latter reported the lowest catastrophizing scores. The chronic pain group (M = 12.94; SD = 5.44) had catastrophizing scores greater than unrelated and nonEur J Pain 19 (2015) 400--407
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Table 3 Comparison between participants reporting having experienced chronic pain with those who reported as not having experienced chronic pain.
a
Age Sexb Male Female PCS scoresa Number of referents listedb 1 2 3 4 Type of primary referentsb Acute injury Headache Menstrual General physical Back pain Others Post-surgical Abdominal pain Emotional Dental pain Context of primary referents Unrelated Non-chronic + worst Chronic Chronic + worst
Participants reporting chronic pain (n = 81)
Participants not reporting chronic pain (n = 101)
M (SD) or n (%)
M (SD) or n (%)
p-value
19.42 (2.27)
19.42 (1.73)
p = 0.989 p = 0.0861
16 (19.8%) 65 (80.3%) 13.23 (6.78)
30 (29.7%) 71 (70.3%) 10.47 (6.40)
48 (59.3%) 23 (28.4%) 8 (9.9%) 2 (2.5%)
60 (59.4%) 32 (31.7%) 6 (5.9%) 3 (3.0%)
22 (27.2%) 12 (14.8%) 7 (8.6%) 6 (7.4%) 6 (7.4%) 12 (14.8%) 5 (6.2%) 5 (6.2%) 3 (3.7%) 3 (3.7%)
26 (25.7%) 21 (20.8%) 13 (12.87%) 15 (14.9%) 4 (4.0%) 8 (7.9%) 4 (4.0%) 1 (0.99%) 4 (4.0%) 5 (5.0%)
15 (18.5%) 19 (23.5%) 17 (21.0%) 30 (37.0%)
48 (47.5%) 53 (52.5%)
p = 0.006 p = 0.716
p = 0.101
–
– –
n, number of participants; PCS, Pain Catastrophizing Scale; Unrelated, pain referent unrelated to either the self-reported chronic or worst pain; Worst pain, worst pain experience used by the participant as a primary referent; Chronic + worst, primary pain referent used by the participant which was self-reported as both chronic pain and worst pain experience; Chronic pain, self-reported chronic pain experience which was not the worst pain experience and reported as a primary referent. a Independent t-tests. b Chi-square tests.
chronic + worst pain and lower than chronic + worst pain group (see Table 2).
the
3.3 Participants endorsing chronic pain Eighty-one of the 182 participants endorsed having experienced chronic pain. Of those reporting chronic pain, the most commonly experienced types of pain included headaches (40.0%) and back pain (25.6%). Thirty-eight of the 81 reporting chronic pain described this pain as also their worst pain experienced. Of these, 30 participants used this as their primary pain referent. Overall, of the 81 individuals self-reporting having experienced chronic pain, 47 referred to it as the primary pain referent. The chronic pain may or may not have also been their worst pain experience. The rest (42.0%) either referred to their worst pain which was not their chronic pain, or pain unrelated to their chronic or worst pain experience. 404 Eur J Pain 19 (2015) 400--407
The results comparing the participants who endorsed having experienced chronic pain with those who did not indicated that age, sex distribution, type and number of referents did not differ significantly between the two groups. Notably though, the catastrophizing scores for the participants who endorsed having experienced chronic pain were significantly higher (M = 13.23; SD = 6.78 vs. M = 10.47; SD = 6.40; p = .006) than those who did not (see Table 3 for a detailed comparison between the two groups).
4. Discussion To the best of the authors’ knowledge, this is the first study to focus on the examination of pain referents used by respondents while completing a dispositional catastrophizing measure. As such, the present study presents a new perspective on the assessment of painrelated catastrophizing. The participants were pro© 2014 European Pain Federation - EFICâ
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vided with generic instructions asking them to think about a time they experienced physical pain while responding to the PCS, without providing a specific pain cue as a possible referent. The results indicated that the participants referred to a variety of pain types. As expected, a majority of them referred to a previous (or perhaps current) pain experience. The most common pain types referred to were painful acute injuries, abdominal pain and headache. The catastrophizing scores did not vary with the type of primary pain referent being used. This is contradictory to the results from a recent study by Ruscheweyh et al. (2011), where the type of pain cue provided during the administration of PCS influenced the level of catastrophizing (Ruscheweyh et al., 2011). It is plausible that the difference in the results is reflective of the methodological differences. Specific referents were provided to the participants in the previous study, whereas in the present study, the referents used by the participants were self-selected. Therefore, it is likely that the participants in the present study referred to pain most relevant to their personal experience, whereas the participants in the previous study, in the previous study may or may not have found the provided pain cues equally relevant in terms of their personal pain experience. The endorsement of experiencing chronic pain by 44.5% of the participants was surprising as undergraduates are usually considered to be healthy young adults when included in research studies. Indeed, there are only a limited number of previous studies focused on the prevalence of pain in college students (Andrasik et al., 1979; Brewer and Karoly, 1992). Only a few experimental pain studies using undergraduates have assessed present pain intensity at baseline (Masedo and Rosa, 2007), and some others have excluded participants with certain ongoing chronic pain conditions (Dixon et al., 2004). The results of the present study suggest that it is essential to inquire about the experience of chronic pain, both past and current, when including non-clinical young adults in pain research studies. Furthermore, participants with self-endorsed chronic pain reported significantly higher catastrophizing scores than those who did not. These results are consistent with the results obtained in studies focused on both clinical and non-clinical populations where individuals with chronic pain report higher pain catastrophizing than those who do not experience pain (Severeijns et al., 2002; Van Damme et al., 2002; de Boer et al., 2012). Almost all of the participants were able to recall and report a previous pain experience that they considered their worst. However, it is noteworthy that while 60% © 2014 European Pain Federation - EFICâ
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of the participants used their worst pain as the primary referent when responding to the pain catastrophizing measure, the remaining 40% of the participants referred to other types of pain unrelated to their worst pain experience. Thus, it appears that a substantial portion of the sample did not consider their worst pain experience as representative of their typical (or dispositional) way of thinking about pain. Furthermore, the level of catastrophizing was significantly associated with the context of the primary referent. The participants who used chronic pain as their primary referent and considered that as their worst pain experience had the greatest catastrophizing scores, followed by participants who used their chronic pain as the primary referent. The lowest catastrophizing scores were reported by participants who referred to pain experiences unrelated to chronic or worst pain as their primary referent. It is not surprising that the personal significance individuals attach to their pain experience predominantly influences their catastrophic cognitions (Roy et al., 1989). This may have important clinical implications. It is possible or experience that a cognitive ‘pairing’ of one’s perception of their chronic pain and worst pain experience adversely influences their coping responses to pain in the present moment or any subsequent pain experience. It is logical to expect that such individuals would have much worse clinical outcomes (Pincus et al., 2006; Edwards et al., 2009; Riddle et al., 2010). Conversely, it is likely that the individuals who are able to cognitively differentiate possible responses to their worst pain experience from present or typical (or less) painful events would have a better potential for positive adaptation to chronic pain (Jensen et al., 2001; Turner et al., 2006, 2007; Thorn et al., 2007). Indeed, recent research in paediatric pain has provided evidence that children who have had an initial aversive experience with pain are more likely to have higher pain ratings on subsequent pain exposure (Noel et al., 2012). It is possible that similar patterns are operational in young adults as well. The individuals with chronic pain who also view this as their worst pain experienced may be at greatest risk for high catastrophizing, as corroborated by the results of the present study, and leading to poor health outcomes. Knowledge of the pain referent to which the individual is responding allows the clinical practitioner to address the specific source of the cognitions and potentially help patients differentiate present from past painful experiences. This would, in turn, help individuals deal with their present episode of pain and potentially improve their pain outcome (Smeets et al., 2006; Turner et al., 2007). Eur J Pain 19 (2015) 400--407
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Although endorsed by only a small proportion of participants, emotional pain such as mental pain, loss of loved ones and pain due to loneliness as a primary pain referent is important since the participants were specifically cued to think about physical pain. In general, when dispositional catastrophizing measures are administered, it is commonly assumed that the respondents think about their physical pain as they are cued to do so in either explicit or vague terms. It may be important to explore whether catastrophic cognitions in relation to emotional pain represent a different construct than pain catastrophizing in response to physical pain or are they essentially similar (MacDonald and Leary, 2005). There are limitations in our study. The participants were not provided a definition of chronic pain, specifically because we wanted to leave the questions as open-ended as possible for the purpose of this exploratory nature of the study. Thus, it is likely that the chronic pain self-identified by participants in the study would not necessarily correspond to standard accepted definitions of chronic pain (e.g., International Association for the Study of Pain; IASP Task Force on Taxonomy, 1994). However, their use of a self-reported pain condition as a referent while responding to the catastrophizing measure indicates that it was a significant pain source for them and relevant to associated catastrophizing thoughts and emotions. The first referent to be listed by the participants was considered their primary referent. However, participants were not explicitly asked to rank order their referents (if they listed more than one). In addition, pain intensity was not assessed at the time of the completion of PCS. Thus, it is not possible to determine whether the referents themselves, or present pain intensity, have a greater influence on the level of catastrophizing. The participants were not asked about the duration of the chronic pain, or if it was currently ongoing. We simply asked them whether they had ever experienced chronic pain. Furthermore, the participants were not inquired about how long ago they had experienced the pain referent. This is a potential limitation as temporal proximity to the pain experience may have influenced the catastrophizing scores. The present study utilizes participants from an undergraduate psychology subject pool and thus perhaps may limit the generalizability of the findings to other age and population groups. However, recruiting undergraduate students as research subjects do not necessarily pose increased problems of validity and generalizability than any other sample groups (Druckman and Kam, 2009). In conclusion, our results suggest that examination of the specific referent used by individuals responding 406 Eur J Pain 19 (2015) 400--407
to a catastrophizing scale should be included as part of the standard assessment process and would add to our understanding of a person’s pain experience and related catastrophic cognitions. This would be relevant to both patient populations and experimental pain research. Finally, it is noteworthy that a large percentage of presumably healthy undergraduates in this sample reported having experienced chronic pain and had much higher levels of catastrophic cognitions than individuals who did not endorse having experienced chronic pain. Thus, whenever presumably healthy participant samples are included, it would be useful to assess what type of pain experience they have had and whether they currently suffer from chronic painful conditions.
Author contributions S.K. analysed the data and wrote the manuscript; B.E.T. conceptualized the study as well as helped write the manuscript; O.B. helped collect and analyse the data; K.L.C. conceptualized parts of the study and collected data. All authors have discussed the results and commented on the manuscript.
Acknowledgements The authors would like to thank all the undergraduate assistants who helped collect data at various stages of this study.
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Edwards, R.R., Cahalan, C., Mensing, G., Smith, M., Haythornthwaite, J.A. (2011). Pain, catastrophizing, and depression in the rheumatic diseases. Nat Rev Rheumatol 7, 216–224. Edwards, R.R., Campbell, C.M., Fillingim, R.B. (2005). Catastrophizing and experimental pain sensitivity: Only in vivo reports of catastrophic cognitions correlate with pain responses. J Pain 6, 338–339. Edwards, R.R., Haythornthwaite, J.A., Smith, M.T., Klick, B., Katz, J.N. (2009). Catastrophizing and depressive symptoms as prospective predictors of outcomes following total knee replacement. Pain Res Manag 14, 307–311. Edwards, R.R., Kronfli, T., Haythornthwaite, J.A., Smith, M.T., McGuire, L., Page, G.G. (2008). Association of catastrophizing with interleukin-6 responses to acute pain. Pain 140, 135–144. Jensen, M.P., Turner, J.A., Romano, J.M. (2001). Changes in beliefs, catastrophizing, and coping are associated with improvement in multidisciplinary pain treatment. J Consult Clin Psych 69, 655–662. Khan, R.S., Ahmed, K., Blakeway, E., Skapinakis, P., Nihoyannopoulos, L., Macleod, K., Sevdalis, N., Ashrafian, H., Platt, M., Darzi, A., Athanasiou, T. (2011). Catastrophizing: A predictive factor for postoperative pain. Am J Surg 201, 122–131. MacDonald, G., Leary, M.R. (2005). Why does social exclusion hurt? The relationship between social and physical pain. Psychol Bull 131, 202– 223. Mankovsky, T., Lynch, M.E., Clark, A.J., Sawynok, J., Sullivan, M.J.L. (2012). Pain catastrophizing predicts poor response to topical analgesics in patients with neuropathic pain. Pain Res Manag 17, 10–14. Masedo, A.I., Rosa, E.M. (2007). Effects of suppression, acceptance and spontaneous coping on pain tolerance, pain intensity and distress. Behav Res Ther 45, 199–209. Noel, M., Chambers, C.T., McGrath, P.J., Klein, R.M., Stewart, S.H. (2012). The influence of children’s pain memories on subsequent pain experience. Pain 153, 1563–1572. Pincus, T., Vogel, S., Burton, A.K., Santos, R., Field, A.P. (2006). Fear avoidance and prognosis in back pain: A systematic review and synthesis of current evidence. Arthritis Rheum 54, 3999–4010. Quartana, P.J., Campbell, C.M., Edwards, R.R. (2009). Pain catastrophizing: A critical review. Expert Rev Neurother 9, 745–758. Riddle, D.L., Wade, J.B., Jiranek, W.A., Kong, X. (2010). Preoperative pain catastrophizing predicts pain outcome after knee arthroplasty. Clin Orthop Relat Res 468, 798–806.
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Roy, R., Thomas, M., Makarenko, P. (1989). Memories of pain: Comparison of ‘worst pain ever’ experienced by senior citizens and college students. Clin J Pain 5, 359–362. Ruscheweyh, R., Nees, F., Marziniak, M., Evers, S., Flor, H., Knecht, S. (2011). Pain catastrophizing and pain-related emotions: Influence of age and type of pain. Clin J Pain 27, 578–586. Severeijns, R., van den Hout, M.A., Vlaeyen, J.W.S., Picavet, H.S.J. (2002). Pain catastrophizing and general health status in a large Dutch community sample. Pain 99, 367–376. Smeets, R.J., Vlaeyen, J.W., Kester, A.D., Knottnerus, J.A. (2006). Reduction of pain catastrophizing mediates the outcome of both physical and cognitive-behavioral treatment in chronic low back pain. J Pain 7, 261–271. Sturgeon, J.A., Zautra, A.J. (2012). State and trait pain catastrophizing and emotional health in rheumatoid arthritis. Ann Behav Med 45, 69– 77. Sullivan, M.J.L., Bishop, S.R., Pivik, J. (1995). The Pain Catastrophizing Scale: Development and validation. Psychol Assess 7, 524–532. Sullivan, M.J.L., Thorn, B.E., Haythornthwaite, J.A., Keefe, F., Martin, M., Bradley, L.A., Lefebvre, J.C. (2001). Theoretical perspectives on the relation between catastrophizing and pain. Clin J Pain 17, 52–64. Thorn, B.E., Pence, L.B., Ward, L.C., Kilgo, G., Clements, K.L., Cross, T., Davis, A.M., Tsui, P.W. (2007). A randomized clinical trial of targeted cognitive behavioral treatment to reduce catastrophizing in chronic headache sufferers. J Pain 8, 938–949. Turner, J.A., Holtzman, S., Mancl, L. (2007). Mediators, moderators, and predictors of therapeutic change in cognitive-behavioral therapy for chronic pain. Pain 127, 276–286. Turner, J.A., Mancl, L., Aaron, L.A. (2006). Short- and long-term efficacy of brief cognitive-behavioral therapy for patients with chronic temporomandibular disorder pain: A randomized, controlled trial. Pain 121, 181–194. Van Damme, S., Crombez, G., Bijttebier, P., Goubert, L., Van Houdenhove, B.A. (2002). A confirmatory factor analysis of the Pain Catastrophizing Scale: Invariant factor structure across clinical and non-clinical populations. Pain 96, 319–324.
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Pain referents used to respond to the Pain Catastrophizing Scale S. Kapoor1, B.E. Thorn1, O. Bandy1, K.L. Clements2 1 Psychology Department, The University of Alabama, Tuscaloosa, USA 2 Department of Behavior and Mental Health, Birmingham Veterans Affairs Medical Center, Birmingham, USA
Correspondence Beverly E. Thorn E-mail: [email protected]; [email protected] Funding sources None. Conflicts of interest None declared. Accepted for publication 27 May 2014 doi:10.1002/ejp.561
Abstract Background: Pain catastrophizing has emerged as a highly important construct in pain research. The Pain Catastrophizing Scale (PCS) is a widely used self-report measure used to determine a person’s level of pain catastrophizing, assumed to be associated with an ongoing, recalled or anticipated pain experience. In practice, instructions for self-reporting catastrophizing typically do not provide a specific pain referent, even when assessing patients with chronic pain. Researchers have noted that it is not known what type of pain participants are referring to when responding to a catastrophizing questionnaire. Method: In the current study, 182 presumably healthy undergraduate students completed the PCS followed by a query regarding the pain referent used to complete the scale. In addition, they were asked if they have ever experienced chronic pain and to list their worst pain experience. Results: The most commonly used primary referents included pain due to acute injury (26.4%), headache (18.0%) and general physical pain (11.5%). The type of primary referent and the number of referents did not influence the catastrophizing scores. However, the catastrophizing scores were influenced by the context of the primary pain referent, i.e., whether the primary pain referent was non-chronic worst pain, both chronic and worst pain, chronic pain or unrelated to either chronic or worst pain. Notably, a larger than expected proportion of participants reported having experienced chronic pain (44.5%; n = 81). Conclusion: The examination of pain referents while responding to a catastrophizing measure would add to our understanding of a person’s pain experience and related catastrophic cognitions.
1. Introduction Pain catastrophizing involves exaggerated maladaptive cognitions or emotions in response to ongoing, anticipated or recalled pain (Sullivan et al., 2001; Quartana et al., 2009). This concept is continuously evolving, and as such, this is one of the several definitions of catastrophizing. The detrimental role of catastrophizing in managing and coping with pain is well documented and catastrophizing is widely acknowledged as an important predictor of pain experience (Campbell et al., 2010a,b; Khan et al., 2011; Mankovsky et al., 400 Eur J Pain 19 (2015) 400--407
2012). Findings are consistent across different study populations, including people with chronic pain as well as individuals experiencing acute or experimental pain (Citero et al., 2007; Edwards et al., 2011; de Boer et al., 2012). Increasingly, the role of situation-specific catastrophizing as compared to dispositional catastrophizing is being examined (Dixon et al., 2004; Campbell et al., 2010a,b; Sturgeon and Zautra, 2012). Catastrophizing measured in the absence of a specific pain referent, sometimes also referred to as trait catastrophizing, is believed to be a dispositional characteristic. On the © 2014 European Pain Federation - EFICâ
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What’s already known about this topic? • Robust empirical evidence that adverse clinical outcomes are associated with pain catastrophizing. • Increasing recognition for the need to comprehensively understand a person’s pain-related catastrophic thoughts. What does this study add? • This study evaluates pain referents used by respondents while completing a dispositional catastrophizing measure. • The study corroborates the importance of the context of the referents and their association with catastrophizing levels.
other hand, catastrophizing measured during a painful experience or immediately following a pain experience is considered situation-specific (Edwards et al., 2005; Campbell et al., 2010a,b). The standard instructions are commonly based upon the assumption that individuals with chronic pain will refer to their chronic pain when responding to the catastrophizing questions, whereas non-clinical study participants will refer to a recalled pain experience; thus, the responses may vary greatly (Ruscheweyh et al., 2011). It has been suggested that not taking into account the pain referent participants used, potentially makes obtained scores difficult to interpret (Campbell et al., 2010a,b). It has been proposed that catastrophizing may represent a latent construct that requires activation via a pain cue, possibly a painful stimulus or a cued recall of a specific pain experience (Beck et al., 1979; Edwards et al., 2008). It is logical to expect that the level of self-reported catastrophizing would depend upon the pain cue, present or recalled. Thus, it is important to inquire and examine the pain referents used when completing a self-report measure of catastrophizing. In the present study, presumably healthy undergraduates in Introductory Psychology classes completed the Pain Catastrophizing Scale (PCS) along with other measures assessing pain-related catastrophic thoughts. The PCS is a widely used, validated 13-item scale with respondents asked to endorse items related to catastrophic pain-related thoughts (Sullivan et al., 1995). Participants did not receive experimentally induced pain, nor were they given any specific instructions for completing the PCS beyond the standard (dispositional) instructions. The latter did not include a specific pain cue as is typically provided in the standard PCS instructions (see Measures section). The foremost © 2014 European Pain Federation - EFICâ
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Table 1 Context of primary pain referents. Terms used in the manuscript Unrelated Non-chronic + worst Chronic + worst
Chronic
Description Pain referent unrelated to either the self-reported chronic or worst pain Pain referent which was self-reported as the worst pain ever experienced, but not chronic Pain referent which was self-reported as both chronic pain as well as the worst pain ever experienced Pain referent which was experienced chronically but was not described as the worst pain experienced
aim of the study was to assess the referents used by the respondents while responding to the PCS. In addition, the association of catastrophizing scores with the type of pain, number and context of the primary referents was examined. Context of the primary pain referent indicates whether the primary pain referent was nonchronic worst pain, both chronic and worst pain, chronic pain or unrelated to either chronic or worst pain (see Table 1).
2. Methods 2.1 Participants Participants in this study included 182 undergraduate students enrolled in Introductory Psychology classes. They received credit towards course research requirements in exchange for completion of the study. The age of the participants was between 17 and 34 years (M = 19.42; SD = 1.82), and 74.0% (n = 136) of the participants were female.
2.2 Procedure The participants were recruited from the Introductory Psychology classes through the university’s Psychology Subject Pool. All the participants who chose to participate were consented prior to their participation in accordance with the Institutional Review Board (IRB) guidelines. There were no specific exclusion or inclusion criteria. Once the participants were consented, each was individually administered the PCS, a brief pain questionnaire and a demographics survey. Other pain-related measures were also administered, which are not a part of the present study. The study was approved by the university’s IRB.
2.3 Measures 2.3.1 Demographics and pain catastrophizing Demographic information pertaining to the age and gender of the participants was collected. The PCS was used to
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measure pain catastrophizing. PCS is a validated 13-item scale examining catastrophizing (Sullivan et al., 1995). This measure requires participants to rate on a 5-point scale from 0 (not at all) to 4 (all the time) how often they experience specific catastrophic thoughts or feelings when in pain. It measures catastrophizing on three dimensions, namely magnification, rumination and helplessness, and the total score for catastrophizing is the sum of the raw scores. The final score is obtained by adding the raw scores on each item. The possible score range was from 0 to 52, with higher scores indicating greater catastrophic thinking. Generic instructions given to participants were as follows: ‘Please write the number that best describes how much each item listed is similar to a thought or feeling you have when you experience physical pain. Before beginning, please reflect on a time when you have experienced physical pain.’
2.3.2 Pain referents A brief pain survey was used to assess the pain referents used by the participants. In this survey, participants were asked to list the type (or types) of pain they were referencing when completing the PCS. The participants could list multiple referents. However, for the present study, the first referent listed was considered the primary referent, and as such, it was included in the analyses. Participants were next asked if they had ever experienced chronic pain (either chronic or intermittent). If participants responded positively to either, they were asked to describe the type of pain they had experienced. The final question asked the participants to list their worst pain experience and its duration.
2.4 Data analyses Descriptive statistics are either reported as means and standard deviations [M (SD)] or frequency and percentages [n (%)], unless otherwise noted. The primary pain referents used by the participants were assigned to content categories by the researchers. Following the initial coding/categorization of all responses (coder A), the primary pain referents were categorized by two other independent coders (coders B and C). This was accomplished by giving both coders the putative categories, the verbatim responses and instructions to either match the response to the provided categories or suggest other categories if there was not a match. Cohen’s kappa was calculated to determine the inter-rater reliability for the categorization of pain referents between coder A and each of the other coders individually. Once the categories of the primary referents were established, the next step of the data analyses was conducted. Frequency statistics are reported for the type of referents used, the number of referents used and the context of the referents used by the participants. When more than one pain referent was listed by the participant, the first referent listed was considered the primary referent and was used in subsequent analyses. For the purpose of examining the context of the primary pain referent, the participants were divided into 402 Eur J Pain 19 (2015) 400--407
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four groups: participants who used a primary pain referent unrelated to or different from either the worst or chronic pain listed (referred to as unrelated); participants using their worst pain as the primary referent (i.e., the primary referent was not their chronic pain experience, referred to as the non-chronic + worst); participants using their chronic pain as the primary referent (which was not described as their worst pain; referred to as chronic); and lastly, participants using their chronic pain as the primary referent which was also reported as their worst pain (referred to as chronic + worst) (see Table 1). Three one-way analyses of variance (ANOVAs) were conducted to examine whether there were any differences in the catastrophizing scores based upon the type of primary referent, the number of referents used and the context of the primary referent used (see Table 2). As an exploratory final step of the analyses, the age, sex, catastrophizing scores and primary referents used by the participants who endorsed having experienced chronic pain were compared with those who did not (see Table 3).
3. Results 3.1 Primary pain referents The initial generation of categories for the primary referents was performed by two of the authors; B.E.T. (principal investigator and corresponding author) and O.B. (co-author) independently came up with categories based upon their interpretations of the most common responses. Consultation to resolve discrepancies resulted in the final categories. Three coders then coded (B.E.T., O.B. and S.K.) all the responses into those categories independently. Ten distinct categories of pain types were created based upon the location and source of pain. These included pain due to acute injury, abdominal pain, headache, menstrual pain, emotional pain, post-surgical pain, back pain, general physical pain, dental pain and others. The category ‘other’ included referents that were used less than two times by participants, such as ear pain, throat pain and pain due to infections. The category of emotional pain included descriptors self-reported by the participants such as, ‘emotional pain’, ‘mental pain’, ‘pain of losing loved ones’, ‘pain of break-up of relationships’ and ‘loneliness’. The inter-rater reliability between coders A and B was κ = 0.984, the reliability between coders A and C was κ =0.846, and between coders B and C was κ = 0.881. The most common types of primary referents were pain due to acute injury (26.4%), headache (18.0%), general physical pain (11.5%) and menstrual pain (10.9%). The number of referents used by the participants ranged from 1 to 4, with the largest percentage of participants reporting a single pain referent (59.3%) and smallest percentage (2.8%) © 2014 European Pain Federation - EFICâ
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Table 2 One-way analyses of variance (ANOVAs) examining differences in the PCS scores based upon the type of primary pain referents, number of referents listed and context of the primary pain referent used by the participants.
n Type of primary referent Acute injury Headache General physical Menstrual Others Back pain Post-surgical Dental pain Emotional Abdominal pain Number of referents listed 1 2 3 4 Context of primary referents Unrelated Non-chronic + worst Chronic + worst Chronic
Overall sample
Comparisons
M
SD
48 (26.4%) 33 (18.0%) 21 (11.5%) 20 (10.9%) 20 (10.9%) 10 (5.5%) 9 (4.9%) 8 (4.4%) 7 (3.8%) 6 (3.3%)
8.93 12.44 10.13 14.08 13.72 12.16 14.40 12.20 12.46 14.13
5.35 7.48 6.41 6.71 7.00 5.86 7.75 6.35 5.71 8.57
108 (59.34%) 55 (30.22%) 14 (7.69%) 5 (2.75%)
12.18 11.29 10.29 9.76
6.67 6.17 9.28 6.70
63 (34.62%) 72 (39.56%) 30 (16.48%) 17 (9.34%)
10.63 11.13 14.59 12.94
6.51 7.11 6.04 5.44
n (%)
182
182
182
F
df
p
η2
1.92
9172
0.052
0.009
0.597
3178
0.618
0.010
2.846
3178
0.039
0.046
N, number of participants; M, mean PCS scores; SD, standard deviations of PCS scores; df, degrees of freedom; η2, eta-squared value for effect size; Unrelated, pain referent unrelated to either the self-reported chronic or worst pain; Non-chronic + worst, worst pain experience used by the participant as a primary referent which was not experienced chronically; Chronic + worst, primary pain referent used by the participant which was self-reported as both chronic pain and worst pain experience; Chronic, self-reported chronic pain experience which was not the worst pain experience and reported as a primary referent.
reporting four pain referents. Further analyses of the context of the primary pain referents of the participants indicated that overall, 39.6% primarily referred to their worst pain experience which was not experienced chronically (non-chronic + worst), 34.6% referred to a pain unrelated to either chronic pain or worst pain (unrelated), 16.5% referred to their chronic pain also described as their worst pain experience (chronic + worst), whereas 9.3% referred to their chronic which was not described as their worst pain (chronic) (see Table 2 for more details).
3.2 Relationship between catastrophizing and primary pain referents The mean PCS score was 11.70 (SD = 6.70) for the overall sample. The ANOVA results indicated that the PCS scores did not vary based upon the number of pain referents listed by the participants [F(3178) = 0.60; p = 0.62; η2 = .01]. For the type of primary pain referent used by participants, the overall difference in PCS scores fell just short of standard levels of statistical significance [F(9172) = 1.92; © 2014 European Pain Federation - EFICâ
p = 0.052; η2 = 0.009]. Follow-up Tukey’s post-hoc tests confirmed that none of the group differences were significant. As the concept of emotional pain and its distinction from physical pain is not very well understood, further analyses were conducted after excluding emotional pain. In addition, the ‘other’ group included a heterogeneous group of pain referents and was also excluded in this secondary exploration. The results were similar [F(7147) = 1.68; p = 0.057; n = 155] (see Table 2). On the contrary, a one-way ANOVA indicated that there was a significant difference between the PCS scores based upon the context of the primary referents [F(3178) = 2.846; p = 0.039; η2 = 0.046]. Least significant difference post-hoc comparisons revealed that chronic + worst pain referent group had significantly higher catastrophizing scores (M = 14.59; SD = 6.04; n = 30) than the non-chronic + worst pain group (M = 11.13; SD = 7.11; n = 72) and the unrelated group (M = 10.63; SD = 6.51; n = 63). The latter reported the lowest catastrophizing scores. The chronic pain group (M = 12.94; SD = 5.44) had catastrophizing scores greater than unrelated and nonEur J Pain 19 (2015) 400--407
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Table 3 Comparison between participants reporting having experienced chronic pain with those who reported as not having experienced chronic pain.
a
Age Sexb Male Female PCS scoresa Number of referents listedb 1 2 3 4 Type of primary referentsb Acute injury Headache Menstrual General physical Back pain Others Post-surgical Abdominal pain Emotional Dental pain Context of primary referents Unrelated Non-chronic + worst Chronic Chronic + worst
Participants reporting chronic pain (n = 81)
Participants not reporting chronic pain (n = 101)
M (SD) or n (%)
M (SD) or n (%)
p-value
19.42 (2.27)
19.42 (1.73)
p = 0.989 p = 0.0861
16 (19.8%) 65 (80.3%) 13.23 (6.78)
30 (29.7%) 71 (70.3%) 10.47 (6.40)
48 (59.3%) 23 (28.4%) 8 (9.9%) 2 (2.5%)
60 (59.4%) 32 (31.7%) 6 (5.9%) 3 (3.0%)
22 (27.2%) 12 (14.8%) 7 (8.6%) 6 (7.4%) 6 (7.4%) 12 (14.8%) 5 (6.2%) 5 (6.2%) 3 (3.7%) 3 (3.7%)
26 (25.7%) 21 (20.8%) 13 (12.87%) 15 (14.9%) 4 (4.0%) 8 (7.9%) 4 (4.0%) 1 (0.99%) 4 (4.0%) 5 (5.0%)
15 (18.5%) 19 (23.5%) 17 (21.0%) 30 (37.0%)
48 (47.5%) 53 (52.5%)
p = 0.006 p = 0.716
p = 0.101
–
– –
n, number of participants; PCS, Pain Catastrophizing Scale; Unrelated, pain referent unrelated to either the self-reported chronic or worst pain; Worst pain, worst pain experience used by the participant as a primary referent; Chronic + worst, primary pain referent used by the participant which was self-reported as both chronic pain and worst pain experience; Chronic pain, self-reported chronic pain experience which was not the worst pain experience and reported as a primary referent. a Independent t-tests. b Chi-square tests.
chronic + worst pain and lower than chronic + worst pain group (see Table 2).
the
3.3 Participants endorsing chronic pain Eighty-one of the 182 participants endorsed having experienced chronic pain. Of those reporting chronic pain, the most commonly experienced types of pain included headaches (40.0%) and back pain (25.6%). Thirty-eight of the 81 reporting chronic pain described this pain as also their worst pain experienced. Of these, 30 participants used this as their primary pain referent. Overall, of the 81 individuals self-reporting having experienced chronic pain, 47 referred to it as the primary pain referent. The chronic pain may or may not have also been their worst pain experience. The rest (42.0%) either referred to their worst pain which was not their chronic pain, or pain unrelated to their chronic or worst pain experience. 404 Eur J Pain 19 (2015) 400--407
The results comparing the participants who endorsed having experienced chronic pain with those who did not indicated that age, sex distribution, type and number of referents did not differ significantly between the two groups. Notably though, the catastrophizing scores for the participants who endorsed having experienced chronic pain were significantly higher (M = 13.23; SD = 6.78 vs. M = 10.47; SD = 6.40; p = .006) than those who did not (see Table 3 for a detailed comparison between the two groups).
4. Discussion To the best of the authors’ knowledge, this is the first study to focus on the examination of pain referents used by respondents while completing a dispositional catastrophizing measure. As such, the present study presents a new perspective on the assessment of painrelated catastrophizing. The participants were pro© 2014 European Pain Federation - EFICâ
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vided with generic instructions asking them to think about a time they experienced physical pain while responding to the PCS, without providing a specific pain cue as a possible referent. The results indicated that the participants referred to a variety of pain types. As expected, a majority of them referred to a previous (or perhaps current) pain experience. The most common pain types referred to were painful acute injuries, abdominal pain and headache. The catastrophizing scores did not vary with the type of primary pain referent being used. This is contradictory to the results from a recent study by Ruscheweyh et al. (2011), where the type of pain cue provided during the administration of PCS influenced the level of catastrophizing (Ruscheweyh et al., 2011). It is plausible that the difference in the results is reflective of the methodological differences. Specific referents were provided to the participants in the previous study, whereas in the present study, the referents used by the participants were self-selected. Therefore, it is likely that the participants in the present study referred to pain most relevant to their personal experience, whereas the participants in the previous study, in the previous study may or may not have found the provided pain cues equally relevant in terms of their personal pain experience. The endorsement of experiencing chronic pain by 44.5% of the participants was surprising as undergraduates are usually considered to be healthy young adults when included in research studies. Indeed, there are only a limited number of previous studies focused on the prevalence of pain in college students (Andrasik et al., 1979; Brewer and Karoly, 1992). Only a few experimental pain studies using undergraduates have assessed present pain intensity at baseline (Masedo and Rosa, 2007), and some others have excluded participants with certain ongoing chronic pain conditions (Dixon et al., 2004). The results of the present study suggest that it is essential to inquire about the experience of chronic pain, both past and current, when including non-clinical young adults in pain research studies. Furthermore, participants with self-endorsed chronic pain reported significantly higher catastrophizing scores than those who did not. These results are consistent with the results obtained in studies focused on both clinical and non-clinical populations where individuals with chronic pain report higher pain catastrophizing than those who do not experience pain (Severeijns et al., 2002; Van Damme et al., 2002; de Boer et al., 2012). Almost all of the participants were able to recall and report a previous pain experience that they considered their worst. However, it is noteworthy that while 60% © 2014 European Pain Federation - EFICâ
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of the participants used their worst pain as the primary referent when responding to the pain catastrophizing measure, the remaining 40% of the participants referred to other types of pain unrelated to their worst pain experience. Thus, it appears that a substantial portion of the sample did not consider their worst pain experience as representative of their typical (or dispositional) way of thinking about pain. Furthermore, the level of catastrophizing was significantly associated with the context of the primary referent. The participants who used chronic pain as their primary referent and considered that as their worst pain experience had the greatest catastrophizing scores, followed by participants who used their chronic pain as the primary referent. The lowest catastrophizing scores were reported by participants who referred to pain experiences unrelated to chronic or worst pain as their primary referent. It is not surprising that the personal significance individuals attach to their pain experience predominantly influences their catastrophic cognitions (Roy et al., 1989). This may have important clinical implications. It is possible or experience that a cognitive ‘pairing’ of one’s perception of their chronic pain and worst pain experience adversely influences their coping responses to pain in the present moment or any subsequent pain experience. It is logical to expect that such individuals would have much worse clinical outcomes (Pincus et al., 2006; Edwards et al., 2009; Riddle et al., 2010). Conversely, it is likely that the individuals who are able to cognitively differentiate possible responses to their worst pain experience from present or typical (or less) painful events would have a better potential for positive adaptation to chronic pain (Jensen et al., 2001; Turner et al., 2006, 2007; Thorn et al., 2007). Indeed, recent research in paediatric pain has provided evidence that children who have had an initial aversive experience with pain are more likely to have higher pain ratings on subsequent pain exposure (Noel et al., 2012). It is possible that similar patterns are operational in young adults as well. The individuals with chronic pain who also view this as their worst pain experienced may be at greatest risk for high catastrophizing, as corroborated by the results of the present study, and leading to poor health outcomes. Knowledge of the pain referent to which the individual is responding allows the clinical practitioner to address the specific source of the cognitions and potentially help patients differentiate present from past painful experiences. This would, in turn, help individuals deal with their present episode of pain and potentially improve their pain outcome (Smeets et al., 2006; Turner et al., 2007). Eur J Pain 19 (2015) 400--407
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Although endorsed by only a small proportion of participants, emotional pain such as mental pain, loss of loved ones and pain due to loneliness as a primary pain referent is important since the participants were specifically cued to think about physical pain. In general, when dispositional catastrophizing measures are administered, it is commonly assumed that the respondents think about their physical pain as they are cued to do so in either explicit or vague terms. It may be important to explore whether catastrophic cognitions in relation to emotional pain represent a different construct than pain catastrophizing in response to physical pain or are they essentially similar (MacDonald and Leary, 2005). There are limitations in our study. The participants were not provided a definition of chronic pain, specifically because we wanted to leave the questions as open-ended as possible for the purpose of this exploratory nature of the study. Thus, it is likely that the chronic pain self-identified by participants in the study would not necessarily correspond to standard accepted definitions of chronic pain (e.g., International Association for the Study of Pain; IASP Task Force on Taxonomy, 1994). However, their use of a self-reported pain condition as a referent while responding to the catastrophizing measure indicates that it was a significant pain source for them and relevant to associated catastrophizing thoughts and emotions. The first referent to be listed by the participants was considered their primary referent. However, participants were not explicitly asked to rank order their referents (if they listed more than one). In addition, pain intensity was not assessed at the time of the completion of PCS. Thus, it is not possible to determine whether the referents themselves, or present pain intensity, have a greater influence on the level of catastrophizing. The participants were not asked about the duration of the chronic pain, or if it was currently ongoing. We simply asked them whether they had ever experienced chronic pain. Furthermore, the participants were not inquired about how long ago they had experienced the pain referent. This is a potential limitation as temporal proximity to the pain experience may have influenced the catastrophizing scores. The present study utilizes participants from an undergraduate psychology subject pool and thus perhaps may limit the generalizability of the findings to other age and population groups. However, recruiting undergraduate students as research subjects do not necessarily pose increased problems of validity and generalizability than any other sample groups (Druckman and Kam, 2009). In conclusion, our results suggest that examination of the specific referent used by individuals responding 406 Eur J Pain 19 (2015) 400--407
to a catastrophizing scale should be included as part of the standard assessment process and would add to our understanding of a person’s pain experience and related catastrophic cognitions. This would be relevant to both patient populations and experimental pain research. Finally, it is noteworthy that a large percentage of presumably healthy undergraduates in this sample reported having experienced chronic pain and had much higher levels of catastrophic cognitions than individuals who did not endorse having experienced chronic pain. Thus, whenever presumably healthy participant samples are included, it would be useful to assess what type of pain experience they have had and whether they currently suffer from chronic painful conditions.
Author contributions S.K. analysed the data and wrote the manuscript; B.E.T. conceptualized the study as well as helped write the manuscript; O.B. helped collect and analyse the data; K.L.C. conceptualized parts of the study and collected data. All authors have discussed the results and commented on the manuscript.
Acknowledgements The authors would like to thank all the undergraduate assistants who helped collect data at various stages of this study.
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