Disengagement from pain: the role of catastrophic thinking about pain

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1 Pain 107 (2004) Disengagement from pain: the role of catastrophic thinking about pain Stefaan Van Damme a,c, *, Geert Crombez a,c, Christopher Eccleston b a Department of Experimental-Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Henri Dunantlaan 2, 9000 Ghent, Belgium b Department of Psychology, University of Bath, Bath, UK c Research Institute for Psychology and Health, Utrecht, The Netherlands Received 15 July 2003; received in revised form 17 September 2003; accepted 25 September 2003 Abstract This paper reports an experimental investigation of attentional engagement to and disengagement from pain. Thirty-seven pain-free volunteers performed a cueing task in which they were instructed to respond to visual target stimuli, i.e. the words pain and tone. Targets were preceded by pain stimuli or tone stimuli as cues. Participants were characterized as high or low pain catastrophizers, using self-reports. We found that the effect of cueing upon target detection was differential for high and low pain catastrophizers. Analyses revealed a similar amount of attentional engagement to pain in both groups. However, we also found that participants high in pain catastrophizing had difficulty disengaging from pain, whereas participants low in pain catastrophizing showed no retarded disengagement from pain. Our results provide further evidence that catastrophic thinking enhances the attentional demand of pain, particularly resulting in difficulty disengaging from pain. The clinical implications of these findings are discussed. q 2003 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. Keywords: Attention; Experimental pain; Catastrophizing 1. Introduction The function of pain to demand attention, interrupt current activity, and generally interfere with a range of cognitive processes, is now well documented in both clinical and non-clinical populations (Eccleston and Crombez, 1999; Pincus and Morley, 2001). The selection of pain over other potential targets of attention is a normal, adaptive process, because pain is associated with danger and the urge to prioritize escape from potential bodily harm. The attentional demand of pain has been studied principally by the exploitation of a primary task paradigm, in which participants are instructed to ignore pain while performing an attention-demanding task. Within this paradigm, the degradation of task performance in the context of pain is used as a measure of attentional disruption by pain (Crombez et al., 1994; Eccleston, 1994). Catastrophic thinking about pain, defined as an exaggerated * Corresponding author. Address: Department of Experimental-Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Henri Dunantlaan 2, 9000 Ghent, Belgium. Tel.: þ ; fax: þ address: stefaan.vandamme@rug.ac.be (S. Van Damme). negative orientation toward the threat of actual or anticipated pain (Sullivan et al., 2001), has been found to enhance attentional disruption by pain in both clinical and non-clinical populations (Crombez et al., 1998a, 2002a). The primary task paradigm was an advance over the more traditional distraction paradigm that dominated attempts to examine attention and pain (Eccleston, 1995). However, its utility is limited to gross measurement of attentional disruption. The specific processes involved in this disruption are not afforded scrutiny. Three components of attention to all forms of threat have been distinguished (Van Damme et al., 2004, in press): (1) shift toward threat, (2) engagement to threat, and (3) disengagement from threat. Van Damme et al. (2002b) investigated engagement to and disengagement from signals of impending pain, using a cueing paradigm. They instructed participants to detect pain stimuli and tone stimuli, preceded by visual signals informing them of the sensory modality of the stimuli. Attention to one modality facilitates the detection of stimuli presented in that modality (engagement), and inhibits the detection of stimuli presented in the other modality (disengagement). Analyses revealed a similar amount of engagement to pain signals and to tone signals. However, /$20.00 q 2003 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. doi: /j.pain

2 S. Van Damme et al. / Pain 107 (2004) participants experienced pronounced difficulty disengaging attention from pain signals, but not from tone signals. This difficulty disengaging from signals of impending pain was particularly strong in participants high in catastrophic thinking about pain. Because this paradigm only allows an investigation of attention to signals of pain, we developed a modification in order to investigate attention to pain itself. We instructed participants to detect the words pain and tone, which were preceded by a pain stimulus or a tone stimulus, serving as attentional cues, or no stimulus. There was an equal number of validly and invalidly cued targets. Engagement was operationalized as the response time benefit of a valid cue compared to no cue. Disengagement was identified as the response time cost of an invalid cue compared to no cue. In line with Van Damme et al. (2002b), we expected to find strong engagement to and retarded disengagement from pain, and we further hypothesized that difficulty disengaging from pain would be particularly pronounced in pain catastrophizers. 2. Method 2.1. Participants Thirty-seven undergraduate psychology students (six males and 31 females; mean age ¼ years; SD ¼ 3.10; range years) participated to fulfil course requirements. All participants gave informed consent and were free to terminate the experiment anytime Apparatus and cueing task Cues consisted of pain stimuli and tone stimuli. Pain stimuli were transcutaneous electrocutaneous stimuli, delivered by an AC stimulator with an internal frequency of 50 Hz, an instantaneous rise and fall time, and a duration of 300 ms. The stimuli were delivered by two Fukuda standard Ag/AgCl electrodes (1 cm diameter) filled with a lubricant. The electrodes were attached to the non-dominant forearm. The skin at the electrode sites was first abraded with a peeling cream to reduce skin resistance. Intensity of the pain stimulus was 0.63 ma. Using the sensory pain words of the Dutch McGill Pain Questionnaire (Vanderiet et al., 1987), it was found that the characteristics of this stimulus were best described as pricking, boring, flickering, electric and cutting (Crombez et al., 1998a). Previous studies have further demonstrated that an electrocutaneous stimulus of this intensity is painful but easy to tolerate, and that the attentional demand of this stimulus is strongly related to the specific threat value of pain (Crombez et al., 1998a). The tone stimulus was a 500 Hz pitched tone (duration of 300 ms) produced by the computer. Target stimuli were the Dutch words for pain ( pijn ) and for tone ( toon ). Targets were presented in white uppercase characters (8 mm high, 5 mm wide) against the black background of an SVGA computer monitor for a duration of 200 ms. The presentation of cue and target stimuli was controlled by a TURBO PASCAL 5.0 program operating in SVGA graphics mode on an IBM compatible 386 computer. Participants were individually tested in a sound-attenuated room designed for psychophysiological experiments. The cueing task required participants to respond with the dominant hand to pain (tone) targets by pressing the left (right) button of a two-button console. Each trial began with a fixation cross (500 ms) in the middle of the screen. The fixation cross was followed at offset by a cue. The target was presented at stimulus onset asynchronies (SOA) of 100, 200, 500, or 700 ms (SOA: time interval between cue onset and target onset). In most trials, a cue and a target were presented (cue target trials). There was no contingency between cues and targets: in half of the cue target trials, the cue was followed by the corresponding target (validly cued trials), whereas in the other half, the cue was followed by the non-corresponding target (invalidly cued trials). In a number of trials, the target was not preceded by a cue (uncued trials). In order to control for cue responding, there was a number of trials in which only a cue and no target was presented (cue only trials). Finally, in order to ensure that participants attended to the screen, a randomly selected digit between one and nine was presented on some trials instead of a cue or a target (digit trials). Participants were asked to report the digit aloud. A trial ended when a participant responded or 2000 ms had elapsed. The inter-trial interval varied among 1500, 2000, and 2500 ms. Experimental duration was approximately 30 min Procedure Preparation phase Participants were informed that the electrocutaneous stimulus stimulates the pain fibres and that most people find this kind of stimulation unpleasant. To familiarise participants with the pain stimulus, they were given a series of electrocutaneous stimuli with increasing intensity (0.032, 0.16, 0.32, and 0.63 ma) Practice phase Participants were instructed to respond to the targets as quickly as possible without sacrificing accuracy. Participants were informed about cues and targets, and they were instructed to respond only to targets. They were informed that on some trials only a digit would appear which they had to report aloud. The practice phase consisted of nine trials: two validly cued trials, two invalidly cued trials, two uncued trials, two cue only trials, and one digit trial. The order of trial presentation was randomized Experiment phase The experiment phase consisted of 108 trials: 24 validly cued trials, 24 invalidly cued trials, 24 uncued trials, 24 cue

3 72 S. Van Damme et al. / Pain 107 (2004) only trials, and 12 digit trials. The order of presentation was randomized with the restriction that no more than two consecutive trials were of the same trial type. SOA levels (100, 200, 500, or 700 ms) were equally distributed across trial type Post-experiment phase After the experiment phase was finished, participants completed a number of questionnaires. As a manipulation check, the valence and arousal of the cues and the targets were assessed using a 9-point numerical graphic rating scale (Lang, 1980). For valence, the scale ranged from a smiling figure (minimum score ¼ 0) to an unhappy figure (maximum score ¼ 9). For arousal, the scale ranged from a sleepy figure with eyes closed (minimum score ¼ 0) to an excited figure with eyes open (maximum score ¼ 9). Furthermore, the predictive value of the cues was assessed. Using an 11-point numerical graphic rating scale (anchored 0 ¼ not at all and 10 ¼ very strong), participants reported to what extent they expected each target after the presentation of each cue. Finally, participants completed the Dutch version of the Pain Catastrophizing Scale (PCS; Crombez et al., 1998a; Sullivan et al., 1995). The PCS is a 13-item scale for both non-clinical and clinical populations. Participants are asked to reflect on past painful experiences and to indicate the degree to which they experienced each of the 13 thoughts or feelings during pain (e.g. I become afraid that the pain may get worse ) on a 5-point scale from 0 (not at all) to 4 (all the time). The Dutch version of the PCS has been shown to be valid and reliable (Van Damme et al., 2002a) Statistical analyses A 2 (pain catastrophizing: low, high) 2 (cue: valid, no, invalid) 2 (target: tone, pain) 4 (SOA: 100, 200, 500, 700 ms) ANOVA with repeated measures was performed upon the mean RTs of each trial type. Because we were interested in comparing attentional processes between high pain catastrophizers and low pain catastrophizers, pain catastrophizing was included as a between-subject variable. We used the median of the PCS ðmed ¼ 19; M ¼ 18:95; SD ¼ 6:50Þ to differentiate between a group of high pain catastrophizers (n ¼ 20; M ¼ 23:90; SD ¼ 3:68; range 19 33) and a group of low pain catastrophizers (n ¼ 17; M ¼ 13:12; SD ¼ 3:48; range 4 18). Available norms show that high pain catastrophizers in our sample are representative for the population of undergraduates (Van Damme et al., 2000). Greenhouse-Geisser corrections (with corrected degrees of freedom) are presented when the sphericity assumption was violated (Mauchly s Test of Sphericity; P, 0:05). As an estimate of effect size, percentage of variance (PV) was reported for the hypothesized effects. Following Cohen s guidelines (Cohen, 1988), effect sizes of 0.01, and 0.25 were used as thresholds to define small, medium and large effects, respectively. 3. Results 3.1. Self-report data Pain cues were more threatening than tone cues. Participants rated pain stimuli ðm ¼ 6:19; SD ¼ 1:41Þ as more negative than tone stimuli ðm ¼ 4:11; SD ¼ 1:94Þ ðfð1; 36Þ ¼ 20:26; P, 0:001Þ; and they rated pain stimuli ðm ¼ 6:03; SD ¼ 2:32Þ as more arousing than tone stimuli ðm ¼ 4:86; SD ¼ 2:12Þ; ðfð1; 36Þ ¼ 6:25; P, 0:05Þ: Similar effects were found for the targets. Participants rated the pain word ðm ¼ 4:68; SD ¼ 1:45Þ as more negative than the tone word ðm ¼ 3:51; SD ¼ 1:54Þ; ðfð1; 36Þ ¼17:81; P, 0:001Þ; and they rated the pain word ðm ¼ 4:95; SD ¼ 2:16Þ as more arousing than the tone word ðm ¼ 4:11; SD ¼ 2:20Þ; ðfð1; 36Þ ¼5:71; P, 0:05Þ: There were no significant differences between high and low pain catastrophizers in their valence ratings of pain stimuli ðfð1; 36Þ ¼ 1:51; nsþ and tone stimuli ðfð1; 36Þ ¼ 0:98; nsþ: Furthermore, high and low pain catastrophizers did not differ in their arousal ratings of pain stimuli ðfð1; 36Þ ¼2:30; nsþ and tone stimuli ðfð1; 36Þ ¼2:54; nsþ: Similarly, there were no significant differences between high and low pain catastrophizers in their valence ratings of the pain word ðfð1; 36Þ ¼0:12; nsþ and the tone word ðfð1; 36Þ ¼0:07; nsþ: Finally, high and low pain catastrophizers did not differ in their arousal ratings of the pain word ðfð1; 36Þ ¼0:38; nsþ and the tone word ðfð1; 36Þ ¼0:02; nsþ: Although there was no contingency between cue type and target type, participants believed that cues predicted targets. After the presentation of the pain stimulus, participants reported a significantly higher expectation of the pain word ðm ¼ 4:93; SD ¼ 2:33Þ compared to the tone word ðm ¼ 3:45; SD ¼ 2:09Þ; Fð1; 36Þ ¼11:90; P ¼ 0:001: Similarly, after the tone stimulus, participants reported a significantly higher expectation of the tone word ðm ¼ 5:03; SD ¼ 2:22Þ compared to the pain word ðm ¼ 3:89; SD ¼ 2:21Þ; Fð1; 36Þ ¼6:86; P, 0:05: Participants had no stronger belief in the predictive value of the pain stimulus as a cue ðm ¼ 1:49; SD ¼ 2:62Þ than in the predictive value of the tone stimulus as a cue ðm ¼ 1:14; SD ¼ 2:64Þ: Participants belief in the predictive value of the pain stimulus as a cue was calculated as the expectancy that the pain stimulus would be followed by the pain word minus the expectancy that the pain stimulus would be followed by the tone word. Similarly, participants belief in the predictive value of the tone stimulus as a cue was calculated as the expectancy that the tone stimulus would be followed by the tone word minus the expectancy that the tone stimulus would be followed by the pain word. High pain catastrophizers had a significantly stronger belief in the predictive value of the pain stimulus as a cue compared to low pain catastrophizers, Fð1; 36Þ ¼6:03; P ¼ 0:019: However, high pain catastrophizers had no stronger

4 belief than low pain catastrophizers in the predictive value of the tone stimulus as a cue, Fð1; 36Þ ¼1:52; ns: 3.2. Response time data S. Van Damme et al. / Pain 107 (2004) Trials with errors ð, 2%Þ and outliers (response times (RT) less than 150 ms and greater than 1500 ms) ð, 1%Þ were omitted from RT analyses. A 2 (pain catastrophizing: low, high) 2 (cue: valid, no, invalid) 2 (target: tone, pain) 4 (SOA: 100, 200, 500, 700 ms) ANOVA with repeated measures was performed upon the mean RTs of each trial type. Pain catastrophizing was included as a between-subject variable. We found a significant main effect of cue, Fð1:64; 57:48Þ ¼7:85; MSE ¼ 2969:49; P, 0:01: Responses were faster when words were preceded by valid cues ðm ¼ 478 msþ compared to no cues ðm ¼ 490 msþ or invalid cues ðm ¼ 494 msþ: Also the main effect of target was significant, Fð1; 35Þ ¼5:09; MSE ¼ 3965:00; P, 0:05; indicating faster responses to the pain word ðm ¼ 483 msþ compared to the tone word ðm ¼ 492 msþ: Furthermore, there was a significant main effect of SOA, Fð3; 105Þ ¼ 7:71; MSE ¼ 3054:14; P, 0:001; indicating slower responses to trials with cue-target overlap ðsoa100 : M ¼ 495 ms; SOA200 : M ¼ 495 ms; SOA500 : M ¼ 473 ms; SOA700 : M ¼ 487 msþ: As our hypotheses relate to the effects of cues upon target detection, we were particularly interested in the interactions containing cue and target factors. The Cue Target interaction effect was not significant ðf, 1Þ: However, we found a significant Pain catastrophizing Cue Target interaction effect, Fð2; 70Þ ¼ 4:30; MSE ¼ 3948:79; P, 0:05: All other interactions were not significant (all Fs, 1:50). Of particular interest to this study was the significant Pain catastrophizing Cue Target interaction, indicating a differential effect of cues upon target detection, dependent upon the level of pain catastrophizing. Therefore we analyzed this effect separately for high and low pain catastrophizers in terms of RT benefits of valid cues and RT costs of invalid cues. For each type of target, we tested whether a valid cue in comparison with no cue facilitated the detection of the target. Significant benefits of a valid cue reflect attentional engagement to the cue. Furthermore, we tested for each type of target whether an invalid cue in comparison with no cue impaired the detection of the target. Significant costs of an invalid cue reflect difficulty disengaging from the cue. Analyses were performed using a priori one-tailed t-tests for dependent samples. All effects are illustrated in Fig High pain catastrophizers We found significant benefits of the tone stimulus as a valid cue, tð19þ ¼ 2:69; P ¼ 0:007; but not of the pain stimulus as a valid cue, tð19þ ¼ 1:55; P ¼ 0:070; reflecting strong attentional engagement to the tone stimulus as a cue Fig. 1. Mean response times as a function of cue stimulus (tone cue stimulus, no cue stimulus, pain cue stimulus) and target (tone word, pain word) in high and low pain catastrophizers. Small bars indicates the standard error of the mean. to detect the tone word, but not to pain stimulus as a cue to detect the pain word. Furthermore, we found significant costs of the pain stimulus as an invalid cue, tð19þ ¼1:87; P ¼ 0:039; but not of the tone stimulus as an invalid cue, tð19þ ¼0:52; ns, reflecting retarded disengagement from the pain stimulus to detect the tone word, but not from the tone stimulus to detect the pain word Low pain catastrophizers There were no significant benefits of the tone stimulus as a valid cue, tð16þ ¼0:17; ns, and the pain stimulus as a valid cue, tð16þ ¼1:04; ns, showing that there was no strong attentional engagement to the pain stimulus to detect the pain word, and to the tone stimulus to detect the tone word. Furthermore, we found significant costs of the tone stimulus as an invalid cue, tð16þ ¼2:83; P ¼ 0:006; but not of the pain stimulus as an invalid cue, tð16þ ¼0:81; ns. Participants had pronounced difficulty disengaging from the tone stimulus to detect the pain word, but not from the pain stimulus to detect the tone word Test between high and low pain catastrophizers Differences between high and low pain catastrophizers were further analyzed using a priori one-tailed t-tests. We tested whether engagement to pain was stronger in high pain catastrophizers than in low pain catastrophizers. The pain stimulus did not facilitate the detection of the pain word more in high pain catastrophizers compared to low pain catastrophizers, tð35þ ¼ 0:21; ns ðpv ¼ 0:00Þ: Furthermore, we tested the hypothesis that disengagement from pain would be more retarded in high versus low pain

5 74 S. Van Damme et al. / Pain 107 (2004) catastrophizers. This hypothesis was supported, tð35þ ¼ 1:86; P ¼ 0:036; with a medium effect size ðpv ¼ 0:10Þ: As expected, high pain catastrophizers had a pronounced difficulty disengaging attention from the pain stimulus to detect the tone word. In contrast, low pain catastrophizers had no difficulty disengaging attention from the pain stimulus to detect the tone word. An interesting yet unexpected finding was that high pain catastrophizers had less difficulty than low pain catastrophizers disengaging attention from the tone stimulus to detect the pain word, tð35þ ¼ 1:84; P ¼ 0:037 ðpv ¼ 0:09Þ: This indicates that high pain catastrophizers were less retarded in disengaging attention from neutral information in order to detect painrelated information, suggesting a rapid shift to pain information in individuals for whom pain has a high threat value. All effects are presented in Fig Effects of expectancies on attentional components Participants belief in the predictive value of the pain stimulus as a cue was not significantly correlated with attentional engagement to the pain stimulus ðr ¼ 0:06; nsþ; and disengagement from the pain stimulus ðr ¼ 0:22; nsþ: Participants belief in the predictive value of the tone stimulus as a cue tended to be negatively correlated with attentional engagement to the tone stimulus ðr ¼ 20:29; P ¼ 0:086Þ; and was not significantly correlated to disengagement from the tone stimulus ðr ¼ 0:01; nsþ: 4. Discussion The main objective of this study was to investigate attentional engagement to and disengagement from pain. Furthermore, we wanted to examine whether these processes were affected by the level of catastrophic thinking about pain. We found a similar amount of attentional engagement to pain in participants high and low in pain catastrophizing. However, as expected, high pain catastrophizers had pronounced difficulty disengaging from pain, compared to low pain catastrophizers. This effect was not short-lived, as it was found across all SOA levels. These results extend the findings of Crombez et al. (1998a), who demonstrated that pain-free volunteers with a high frequency of catastrophic thinking about pain, had pronounced task interference when pain was administered. However, Crombez et al. (1998a) used a primary-task paradigm, as a result of which it was not possible to identify which attentional component caused task disruption. Our findings suggest that it is in particular the inability to disengage attention from pain and shift it to other task demands that is affected by catastrophic thinking about pain. This is in line with the study of Van Damme et al. (2002b), who found that pain catastrophizing was related to retarded disengagement from but not to engagement to signals of impending pain. It is possible that expectancies have played a role in the retarded disengagement from pain in pain catastrophizers. Indeed, self-reports indicated that high pain catastrophizers had a stronger belief than low pain catastrophizers in the predictive value of the pain stimulus as a cue. However, participants belief in the predictive value of the pain stimulus as a cue was not significantly correlated with disengagement from the pain stimulus. This suggests that expectancies did not mediate between catastrophic thinking about pain and difficulty disengaging from pain in our sample. This is in contrast with the study of Van Damme et al. (2002b), who found that the relation between catastrophic thinking about pain and retarded disengagement from signals of impending pain was mediated by participants expectancies that the pain signal would be followed by pain. An alternative explanation for these effects may be that the threatening context of the experiment, i.e. the use of pain stimuli, activated pain schemata, representing the sensory, spatial, temporal, and affective properties of the pain experience (Pincus and Morley, 2001). Activation of pain schemata may elicit a negative state, increasing the accessibility of schema-congruent information, and interfering with the processing of schema-incongruent information (Bower et al., 1981). For example, in a study of Seltzer and Yarczower (1991), it was found that exposure to aversive stimulation increased the retrieval of negative words, and decreased the encoding of positive words, regardless of whether they were accompanied by a pain stimulus. Pain schemata may be activated more swiftly and may contain more excessively negative and pessimistic information in pain catastrophizers (Sullivan et al., 2001). The activation of pain schemata, favouring the selection of pain-related information over pain-irrelevant information may explain why pain catastrophizers had pronounced difficulty disengaging from the pain stimulus in order to detect the tone word. Furthermore, schemata activation by the threatening context of the experiment may also account for the finding that high pain catastrophizers had less difficulty disengaging from the tone in order to detect the pain word compared to low pain catastrophizers. The results of this study corroborate the idea that retarded disengagement is a prominent component of attention to pain in high pain catastrophizers. Our findings may have clinical relevance. It is suggested that attention is not engaged more strongly to pain than to stimuli in other sensory modalities, such as vision and audition. Furthermore, attentional engagement to pain appears to be independent from the level of catastrophic thinking about pain. In contrast, only participants high in catastrophic thinking about pain showed difficulty disengaging from pain. Applied to the situation of the chronic pain patient, a sustained difficulty disengaging attention from pain sensations and shifting to other demands in the environment, may be an important factor in maintaining pain and disability. Indeed, the inability to disengage from attentional

6 S. Van Damme et al. / Pain 107 (2004) disruption by pain may result in a clinical pattern of heightened pain experience (Crombez et al., 2004; in press McDermid et al., 1996), avoidance behaviour (Asmundson et al., 1997; Crombez et al., 1998b), worry (Aldrich et al., 2000), and emotional distress (McCracken, 1997). Therefore, in clinical practice, traditional attentional distraction strategies may not be effective in high pain catastrophizers. It may be more useful to reduce the threat value of pain, using exposure techniques that disconfirm the belief of catastrophic outcomes (Crombez et al., 2002b; Goubert et al., 2002; Vlaeyen et al., 2002). In addition, a useful alternative to distraction may be attentional regulation (Elliot and Eccleston, 2003). Because interruption by pain is an inescapable fact of life, dynamic switching between pain and other demands is necessary to cope with pain (Eccleston and Crombez, 1999). Attentional regulation implies that chronic pain patients learn to regulate their attention to pain by re-engaging with positive, changeable, and controllable aspects of themselves and their environment (Elliot and Eccleston, 2003). There is a number of issues that need further consideration. First, we found no facilitated engagement to pain in both high and low pain catastrophizers. One possible explanation is that the use of pain stimuli as cues may have resulted in a general interference, reducing the RT benefits of pain stimuli as valid cues. This is in line with studies investigating the effects of pain on the encoding of information. For example, Kuhajda et al. (2002) found in a sample of chronic headache patients that participants who had pain during the encoding of affective words, were significantly slower judging the words as positive or negative. Second, we found that high but not low pain catastrophizers had a strong attentional engagement to the tone. A possible explanation of this finding is that the tone, because of its safety value, is more relevant to high pain catastrophizers compared to low pain catastrophizers. This greater relevance of the tone may have allowed high pain catastrophizers to direct attention more easily to the corresponding tone target. Third, the finding that low pain catastrophizers showed difficulty disengaging from the tone stimulus to detect the pain word, but no difficulty disengaging from the pain stimulus to detect the tone word, might be explained by inhibited processing of painrelated stimuli. As these stimuli are perceived as only mildly threatening by low pain catastrophizers, this explanation is in line with Mogg and Bradley (1998), who argued that the attentional system inhibits the thorough processing of stimuli with a low threat value. Fourth, it is important to note that this study was conducted in pain-free volunteers, using experimental pain stimuli. 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