Induced fear reduces the effectiveness of a placebo intervention on pain (original) (raw)
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PLOS ONE
The role of state anxiety and state fear in placebo effects is still to be determined. We aimed to investigate the effect of fear of movement-related pain (FMRP) and contextual pain related anxiety (CPRA) on the magnitude of placebo analgesia induced by verbal suggestion. Fifty-six female participants completed a modified voluntary joystick movement paradigm (VJMP) where half participated in a predictable pain condition (PC), in which one of the joystick movements is always followed by pain and the other movement is never followed by pain, and half in an unpredictable pain condition (UC), in which pain was delivered unpredictably. By varying the level of pain predictability, FMRP and CPRA were induced in PC and UC respectively. Colour stimuli were presented at the beginning of each trail. Half of the participants were verbally informed that the green or red colour indicated less painful stimuli (experimental groups), the other half did not receive any suggestion (control groups). We measured self-reported pain intensity, expectancy of pain intensity (PC only), pain related fear and anxiety (eyeblink startle response and self-ratings) and avoidance behaviour (movement-onset latency and duration). The results indicate that the placebo effect was successfully induced in both experimental conditions. In the PC, the placebo effect was predicted by expectancy. Despite the fact that FMRP and CPRA were successfully induced, no difference was found in the magnitude of the placebo effect between PC and UC. Concluding, we did not find a divergent effect of fear and anxiety on placebo analgesia.
Is fear of pain related to placebo analgesia?
Journal of Psychosomatic Research, 2010
Objective: Verbal information that a painkiller has been administered generates an expectation of pain relief which in turn decreases pain. This expectation-based pain reduction is termed placebo analgesia. We hypothesized that fear of pain would be related to higher stress and pain intensity and to reduced placebo analgesia. Methods: Sixty-three students (30 females) participated in a Two-Condition (placebo, natural history)×Five-Test (one pretest, four post-tests) within-subjects design. Heat pain was induced by a 30×30-mm contact thermode to the medial volar forearm. Each pain test lasted for 4 min at a temperature of 46°C. Stress, arousal, and pain intensity and pain unpleasantness were rated on 100-mm visual analogue scales. Results: Fear of pain was related to higher anticipatory stress and to higher stress and pain intensity during pain. Fear of pain was also related to reduced placebo analgesic responding. Conclusion: Fear of pain was positively related to stress both during pain and in the anticipation of pain, and negatively related to placebo analgesia. Previous research has indicated a role for increased stress in the nocebo response, and the present findings suggest that decreased stress may strengthen the placebo response.
The additive impact of anxiety and a placebo on pain
Pain Medicine, 2001
Objective. We investigated the effects of pain anxiety and a placebo/nocebo/neutral intervention on ice water-induced pain. Design. We divided 72 volunteers into high-and low-anxiety groups before randomly assigning them to experimental and control subgroups. Method. Participants completed preimmersion tests of pain anxiety, pain worry, and mood. We scored first immersion pain behavior, experience, and intensity. Each subgroup then received an instruction designed to elicit a positive (placebo), negative (nocebo), or neutral response. After repeating the pain worry test, we gathered second immersion pain scores, and participants repeated the mood test, completed the treatment credibility measure, and were debriefed. Outcome Measures. We used the Pain Anxiety Symptom Scale; self-rating Likert-type scales for pain worry, pain intensity, and pain-coping; the Multiple Affect Adjective Checklist (mood); timed measurements for pain threshold and pain tolerance; and a treatment credibility scale. Results. Pain anxiety and the placebo interventions significantly altered participants' pain scores, with best-to-worse scores reported by the low pain-anxiety/placebo, high anxiety/placebo, low anxiety/ neutral, low anxiety/nocebo, high anxiety neutral, and high anxiety/nocebo groups. The high painanxiety group demonstrated the greatest response to the placebo/nocebo intervention in the expected directions in pain, worry, and anxious mood scores and in decreased self-confidence in managing pain (this was also negatively affected by the nocebo in each pain-anxiety group). Conclusion. This study demonstrates that the interaction of the personality variable of pain anxiety with the placebo/nocebo response has an impact on pain, worry, and mood.
Fear and pain: Investigating the interaction between aversive states
Journal of Abnormal Psychology, 2006
Pain and fear often co-occur and appear to interact, although the nature and direction of their relation is not clearly delineated. The present study investigates how exposure to the experience of one of these states subsequently affects responding to the other. Pressure stimulation and carbon dioxide-enriched air (CO 2 ) were used to induce pain and fear, respectively, in 48 healthy individuals. The order in which the stimuli were introduced was manipulated, as was the CO 2 level. Measures of overt behavior, physiological responding, and self-report were obtained; analyses of stimuli effects generally supported their ability to produce pain or fear. Results indicate that the stimulus rated as the most aversive, the higher level of CO 2 , led to the highest levels of distressed responding across dependent measures. This pattern was replicated for the stimuli found to be less aversive (i.e., pressure stimulation and low-level CO 2 , respectively). The authors conclude that fear and pain, in and of themselves, do not dictate the nature of their interaction; the most important factor is how aversive they are perceived to be in relation to one another.
The fear potentiated startle effect
Integrative Physiological and Behavioral Science, 1991
A differential conditioning study examined whether an acoustic startle probe, presented during extinction of an aversively conditioned visual stimulus, potentiated the reflex eyeblink response in humans and whether this potentiation varied with the change in affective valence of the conditioned stimulus. Sixty college students were randomly assigned to view a series of two slides, depicting either tmpleasant/highly arousing, unpleasant/moderate arousing, neutral/calm, pleasant/moderate arousing or pleasant/hlghly arousing scenes and objects (duration: 8 see). During preconditioning (8 trials) and extinction (24 trials) acoustic startle probes (white noise bursts [50 ms; 95 dBA] were administered during and between slide presentation). During acquisition (16 trials) CS+ was reinforced by an electric shock. Startle response magnitudes significantly increased from preconditioning to extinction and were substantially larger to CS+. Conditioned startle reflex augmentation linearly increased with the pleasantness of the slides. Furthermore, subjects showed a greater post-conditioning increase of judged aversiveness to slides that they had previously reported to be more pleasant, exactly paralleling the startle reflex results.
Advances in psychosomatic medicine, 2004
The psychological behaviorism theory of pain unifies biological, behavioral, and cognitive-behavioral theories of pain and facilitates development of a common vocabulary for pain research across disciplines. Pain investigation proceeds in seven interacting realms: basic biology, conditioned learning, language cognition, personality differences, pain behavior, the social environment, and emotions. Because pain is an emotional response, examining the bidirectional impact of emotion is pivotal to understanding pain. Emotion influences each of the other areas of interest and causes the impact of each factor to amplify or diminish in an additive fashion. Research based on this theory of pain has revealed the ameliorating impact on pain of (1) improving mood by engaging in pleasant sexual fantasies, (2) reducing anxiety, and (3) reducing anger through various techniques. Application of the theory to therapy improved the results of treatment of osteoarthritic pain. The psychological behavi...
Pain, 1999
Placebo analgesia was produced by conditioning trials wherein heat induced experimental pain was surreptitiously reduced in order to test psychological factors of expectancy and desire for pain reduction as possible mediators of placebo analgesia. The magnitudes of placebo effects were assessed after these conditioning trials and during trials wherein stimulus intensities were reestablished to original baseline levels. In addition, analyses were made of the in¯uence of these psychological factors on concurrently assessed pain and remembered pain intensities. Statistically reliable placebo effects on sensory and affective measures of pain were graded according to the extent of surreptitious lowering of stimulus strength during the manipulation trials, consistent with conditioning. However, all of these effects were strongly associated with expectancy but not desire for relief. These results show that although conditioning may be suf®cient for placebo analgesia, it is likely to be mediated by expectancy. The results further demonstrated that placebo effects based on remembered pain were 3 to 4 times greater than those based on concurrently assessed placebo effects, primarily because baseline pain was remembered as being much more intense than it actually was. However, similar to concurrent placebo effects, remembered placebo effects were strongly associated with expected pain levels that occurred just after conditioning. Taken together, these results suggest that magnitudes of placebo effect are dependent on multiple factors, including conditioning, expectancy, and whether analgesia is assessed concurrently or retrospectively. q 1999 International Association for the Study of Pain. Published by Elsevier Science B.V.