C. Richard Chapman

Suffering: the contributions of persistent pain

Pain is a perceived threat or damage to ones biological integrity. Suffering is the perception of serious threat or damage to the self, and it emerges when a discrepancy develops between what one expected of ones self and what one does or is. Some patients who experience sustained unrelieved pain suffer because pain changes who they are. At a physiological level, chronic pain promotes an extended and destructive stress response characterised by neuroendocrine dysregulation, fatigue, dysphoria, myalgia, and impaired mental and physical performance. This constellation of discomforts and functional limitations can foster negative thinking and create a vicious cycle of stress and disability. The idea that ones pain is uncontrollable in itself leads to stress. Patients suffer when this cycle renders them incapable of sustaining productive work, a normal family life, and supportive social interactions. Although patients suffer for many reasons, the physician can contribute substantially to the prevention or relief of suffering by controlling pain. Suffering is a nebulous concept for most physicians, and its relation to pain is unclear. This review offers a medically useful concept of suffering that distinguishes it from pain, accounts for the contributory relation of pain to suffering by describing pain as a stressor, and explores the implications of these ideas for the care of patients.

Pain, depression, and illness behavior in a Pain Clinic population

&NA; The relationship between depression, illness behavior and persistent pain was studied in 100 patients referred to the University of Washington Hospital Pain Clinic. The instruments used were the Illness Behavior Questionnaire (IBQ) and the Levine‐Pilowsky Depression Questionnaire (LPD). To delineate those aspects of illness behavior characteristic of the Pain Clinic group, their scores were compared to those attained on the IBQ by a Family Medicine Clinic sample. The Pain Clinic group showed greater conviction of disease and somatic preoccupation than the comparison group. Further, they were reluctant to consider their health problems in psychologic terms, and denied current life problems. The Pain Clinic groups performance on the LPD indicated a low degree of depressive affect overall and few patients manifesting a depressive syndrome. The association between IBQ and depression scores suggests that the predominant clinical pattern presented by pain clinic patients is best characterized as a form of “abnormal illness behavior”.

Psychological interventions for chronic pain: a critical review. I. Relaxation training and biofeedback

There has been substantial recent application of psychological techniques‘in pain management, often within the context of multidisciplinary pain clinics. It is now important to ask whether these procedures are meeting the goals they purport to achieve and how they compare with one another. In part I of this two-part article, we provide a background for the problem of chronic pain and the current psychological conceptualizations of pain phenomena. Research on the effectiveness of relaxation training and biofeedback is also discussed. In part II, studies of the efficacy of operant conditioning,. hypnosis, and co~itive-behavioral therapy are examined. Finally, the comparative efficacy of these interventions, salient methodological issues, and suggestions for future research are considered.

Psychological interventions for chronic pain: a critical review. II Operant conditioning, hypnosis, and cognitive-behavioral therapy

This is the second part of a review examining the evidence for and against psychological inte~entions for chronic pain problems. Part I, published as the preceding article, dealt with relaxation training and biof~back, which have in common the rationale that pain may emerge and persist in response to disturbance in physiological processes. Studies to date evaluating the effectiveness of relaxation training and alpha, electromyographic, finger temperature, and other types of biofeedback led us to conclude, in agreement with several other recent reviews [6,67,75] that: (a) biofeedback with home practice of relaxation is effective in reducing migraine and tension headache activity, (b) relaxation training alone is also effective for migraine and tension headaches, and (c) there is no evidence that biofeedback is superior to relaxation training with these headache populations. Both approaches have largely ignored the learning processes and cognitive factors, as well as social, cultural, and economic variables that critically influence chronic pain problems. Here we review and critically evaluate studies of the following approaches that focus on one or more of these variables: operant conditioning, hypnosis, and cognitive-behavioral therapies for chronic pain. Finally, comparative efficacy of the different interventions is considered, and suggestions are made for improvements in future research.

Brain evoked potentials are functional correlates of induced pain in man

&NA; Electrical potentials evoked by 5 intensities of painful dental stimulation were recorded at the scalp. During testing, volunteers indicated subjective painfulness by verbal pain ratings and visual analogue scales. Evoked potentials (EPs) to each intensity, observed between 50 and 400 msec, were characterized by 4 waveform components. The peak‐to‐peak amplitudes, but not the peak latencies, of all 4 EP components systematically increased with increased stimulation. The amplitudes of the two earlier components correlated with stimulus intensity when the effect of subjective painfulness was controlled, but this was not the case for the later components. In contrast, the amplitudes of the two later components were associated with subjective painfulness but not with stimulus intensity. A strong linear relationship was observed between subjective painfulness and peak‐to‐peak amplitude for the EP component observed between 175 and 260 msec. The data suggest that the earlier EP components may reflect sensory transmission processes while the later components indicate brain activity when pain is perceived.

Toward validation of pain measurement tools for children: a pilot study

&NA; We undertook to explore the validity of pain measurement tools for use in children in the postoperative period. The general approach was to determine the extent to which a measurement tool conformed with the clinical expectations about pain in the postoperative period; namely, that pain is low prior to surgery, increases following surgery, decreases with pain medication and decreases over time following surgery. In children aged 6 months to 3 years, we evaluated the CHEOPS and Observer pain scales. In children 3–6 years of age, we used the CHEOPS, Observer and Faces scale. In children 6–12 years of age, we studied the CHEOPS, Faces and visual analogue scales. In all instances, each of the scales conformed with the clinical expectations about pain following surgery. In addition, these scales were correlated with each other. Within the limitations of the measurement techniques used, these data provide support for the validity of the measurement tools evaluated.

Opioid Pharmacotherapy for Chronic Non-Cancer Pain in the United States: A Research Guideline for Developing an Evidence-Base

UNLABELLED This document reports the consensus of an interdisciplinary panel of research and clinical experts charged with reviewing the use of opioids for chronic noncancer pain (CNCP) and formulating guidelines for future research. Prescribing opioids for chronic noncancer pain has recently escalated in the United States. Contrasting with increasing opioid use are: 1) The lack of evidence supporting long-term effectiveness; 2) Escalating misuse of prescription opioids including abuse and diversion; and 3) Uncertainty about the incidence and clinical salience of multiple, poorly characterized adverse drug events (ADEs) including endocrine dysfunction, immunosuppression and infectious disease, opioid-induced hyperalgesia and xerostomia, overdose, falls and fractures, and psychosocial complications. Chief among the limitations of current evidence are: 1) Sparse evidence on long-term opioid effectiveness in chronic pain patients due to the short-term time frame of clinical trials; 2) Insufficiently comprehensive outcome assessment; and 3) Incomplete identification and quantification of ADEs. The panel called for a strategic interdisciplinary approach to the problem domain in which basic scientists and clinicians cooperate to resolve urgent issues and generate a comprehensive evidence base. It offered 4 recommendations in 3 areas: 1) A research strategy for studying the effectiveness of long-term opioid pharmacotherapy; 2) Improvements in evidence-generation methodology; and 3) Potential research topics for generating new evidence. PERSPECTIVE Prescribing opioids for CNCP has outpaced the growth of scientific evidence bearing on the benefits and harms of these interventions. The need for a strong evidence base is urgent. This guideline offers a strategic approach to creating a comprehensive evidence base to guide safe and effective management of CNCP.

Nitrous Oxide Effects on Cerebral Evoked Potential to Pain: Partial Reversal with a Narcotic Antagonist

The effect of naloxone, 0.4 mg, on the analgesia induced by nitrous oxide, 33 per cent, in oxygen, was studied in 12 volunteers. Results of previous investigations in animals suggested that endogenous opiate-like substances may play a major role in the analgesic mechanism of nitrous oxide, but the issue had not been studied in man. Cerebral evoked potentials (CEP) to painful tooth-pulp electrical shocks were obtained before and after inhalation of nitrous oxide, and after nitrous oxide plus naloxone, 0.4 mg, in one session; and before and after inhalation of room air, and after room air plus naloxone, 0.4 mg, in another session. CEP waveforms observed between 80 and 350 msec were quantified in terms of three peak-to-peak amplitudes and peak latencies. Nitrous oxide decreased each of the waveform peak-to-peak amplitudes 48 per cent. Naloxone restored the peak-to-peak amplitude of the negative-going wave occurring between 100 and 175 msec. Nitrous oxide also increased the negative peak latency at 175 msec, and naloxone restored this peak latency to normal levels. Neither room air nor room air plus naloxone altered CEP amplitudes or latencies. Over time a significant trend in subjective reports of decreased pain intensity with nitrous oxide and partially increased pain with naloxone was evident. These findings demonstrate that some of the effects of nitrous oxide on the central nervous system can be reversed by naloxone.

Detection and decision factors in pain perception in young and elderly men

&NA; The effect of age on ability to discriminate between levels of electrical stimulation of tooth pulp and willingness to report shocks as painful was evaluated using the Sensory Decision Theory. While threshold did not increase with age for tooth pulp stimulation as is often observed for thermal pain thresholds, a significant age deficit in ability to discriminate between suprathreshold shocks was observed. Significant changes with age in willingness to report the electrical shocks as painful were also observed. These results indicate that changes with age in pain perception are complex, involving not only possible discrimination deficits but also changes in bias for and against labeling noxious events as painful. These findings stress the need for within individual comparisons of laboratory techniques for evoking acute pain experiences where variables such as age are under consideration.

Sensory decision theory methods in pain research: A reply to Rollman☆

&NA; Positive reviews of the developing literature on Sensory Decision Theory (SDT) pain research have been provided by Lloyd and Appel [21] and Hall [17]. In contrast, Rollman [24] has criticized the application of SDT methodology to the study of pain, arguing that it is “an error in logic to utilize SDT parameters to reach definitive conclusions about mechanisms altered during pain modulation”, and he has attacked the procedures employed by decision theory researchers in data collection and analysis. This paper is a response to Rollman written from the perspective of a single group of SDT pain researchers. I will first bring to issue certain fundamental statements that appear recurrently throughout Rollmans paper, and I will argue that many of his criticisms lack substance because these assertions are inappropriate. In addition, I will deal briefly with some of Rollmans specific methodologic criticisms, limiting my comments to those points that are salient to the multidisciplinary audience of this journal, and I will briefly describe the pain model that has been implicit in the work of our laboratory group.