Zina Trost

Reducing Social Stress Elicits Emotional Contagion of Pain in Mouse and Human Strangers.

Empathy for anothers physical pain has been demonstrated in humans [1] and mice [2]; in both species, empathy is stronger between familiars. Stress levels in stranger dyads are higher than in cagemate dyads or isolated mice [2, 3], suggesting that stress might be responsible for the absence of empathy for the pain of strangers. We show here that blockade of glucocorticoid synthesis or receptors for adrenal stress hormones elicits the expression of emotional contagion (a form of empathy) in strangers of both species. Mice and undergraduates were tested for sensitivity to noxious stimulation alone and/or together (dyads). In familiar, but not stranger, pairs, dyadic testing was associated with increased pain behaviors or ratings compared to isolated testing. Pharmacological blockade of glucocorticoid synthesis or glucocorticoid and mineralocorticoid receptors enabled the expression of emotional contagion of pain in mouse and human stranger dyads, as did a shared gaming experience (the video game Rock Band) in human strangers. Our results demonstrate that emotional contagion is prevented, in an evolutionarily conserved manner, by the stress of a social interaction with an unfamiliar conspecific and can be evoked by blocking the endocrine stress response.

Perceived injustice: a risk factor for problematic pain outcomes.

Background:Emerging research suggests that perceptions of injustice after musculoskeletal injury can have a significant impact on a number of pain-related outcomes. Aims:The purpose of this paper is to review evidencelinking perceptions of injustice to adverse pain outcomes. For the purposes of this paper, perceived injustice is defined as an appraisal cognition comprising elements of the severity of loss consequent to injury (“Most people don’t understand how severe my condition is”), blame (“I am suffering because of someone else’s negligence”), a sense of unfairness (“It all seems so unfair”), and irreparability of loss (“My life will never be the same”). Results:Cross-sectional studies show that high scores on perceptions of injustice are correlated with pain catastrophizing, fear of movement, and depression. Prospective studies show that high scores on perceived injustice are a prognostic indicator of poor rehabilitation outcomes and prolonged work disability. Research shows that perceptions of injustice interfere not only with physical recovery after injury, but perceptions of injustice also impact negatively on recovery of the mental health problems that might arise subsequent to traumatic injury. Although research has yet to address the process by which perceptions of injustice impact on pain-related outcomes systematically; possible mechanisms include attentional disengagement difficulties, emotional distress, maladaptive coping, heightened displays of pain behavior, anger, and revenge motives. Conclusions:Perceived injustice appears to be associated with problematic health and mental health recovery trajectories after the onset of a pain condition. Future directions for research and treatment are addressed.

Anger differentially mediates the relationship between perceived injustice and chronic pain outcomes.

Summary Anger variables differentially mediated the relationships between perceived injustice and pain intensity, depressive symptoms, and disability. Results are discussed in terms of implications for intervention. ABSTRACT Emerging evidence suggests that perceived injustice is a risk factor for adverse outcomes associated with chronic pain. To date, however, the processes by which perceived injustice impacts on pain outcomes remain speculative. Evidence from several lines of research suggests that anger may mediate the relationship between injustice and pain outcomes. However, this relationship has not been empirically tested in patients with chronic pain. Thus, the purpose of this study was to examine whether anger mediates the relationships between perceived injustice and pain intensity, depressive symptoms, and self‐reported disability. One hundred and seventy‐three individuals with chronic musculoskeletal pain completed self‐report measures of perceived injustice, anger, pain intensity, depressive symptoms, and disability. Consistent with previous research, high scores on a measure of perceived injustice were associated with greater pain, more severe depressive symptoms, and more pronounced disability. Hierarchical regression analyses indicated that anger variables completely mediated the relationship between perceived injustice and pain intensity, and partially mediated the relationship between perceived injustice and depressive symptoms. Anger did not mediate the relationship between perceived injustice and self‐reported disability. The Discussion addresses the theoretical and clinical implications of the findings.

Cognitive dimensions of anger in chronic pain

Anger has long been recognized as an integral part of pain experience [1,19]. Reviews highlight the deleterious effect of anger on social, clinical, and functional outcomes [9,22,32]. Anger has been discussed as an aversive emotional state ranging from mild irritation to fury [25], and comprising specific cognitive attributions and action tendencies [21,34]. Anecdotal and empirical data suggest that anger is commonplace among chronic pain sufferers [32]. In their 2003 review, Greenwood et al. [22] identified anger as an important target of research and behavioral management; since that review, research has highlighted biopsychosocial mechanisms through which anger may affect pain experience [5,9,33]. However, to date, no systematic line of research has addressed the cognitive dimensions of anger in chronic pain. We believe that elucidating these facets of anger in pain sufferers might strengthen the empirical foundation for more effective treatment. Although not exhaustive, the current review highlights potential sources of anger among pain sufferers by drawing on conceptualizations from existing social psychological theory and newly evolving lines of research. On this basis, we discuss the role of anger in treatment settings, and possible frameworks for research and intervention.

Pain-related fear and avoidance of physical exertion following delayed-onset muscle soreness

&NA; The current study examined the relationship between pain‐related fear, physical performance, and pain‐related interference in the context of experimentally induced pain to the lower back. Thirty healthy participants completed a test of maximal trunk strength before and after induction of delayed‐onset muscle soreness (DOMS) to the trunk extensors. Pain‐related fear (Tampa Scale of Kinesiophobia and Pain Anxiety Symptom Scale) was assessed prior to DOMS induction, and measures of current pain and pain‐related interference with life activities were obtained 1 day after DOMS induction. As predicted, pain‐related fear was not related to strength production prior to DOMS induction. However, following DOMS induction, pain‐related fear predicted reduced maximal strength production, individual decrement in maximal strength performance, and increased pain‐related interference in life activities. Current pain intensity and anthropometric factors did not contribute significantly to these outcome measures. To our knowledge, this is the first study to identify the impact of pain‐related fear on physical performance among a healthy group of individuals following experimental acute low back injury. The findings extend previous research on psychological variables and simulated injury, and suggest that pain‐related fear may be an important vulnerability factor in development of disability following acute pain experience. Following induced delayed‐onset muscle soreness to the lower back, pain‐related fear predicted physical performance and interference in life activities among healthy participants, above pain intensity and anthropometric factors.

Social modulation of facial pain display in high-catastrophizing children: An observational study in schoolchildren and their parents

&NA; The present study examined existing communal and operant accounts of children’s pain behavior by looking at the impact of parental presence and parental attention upon children’s pain expression as a function of child pain catastrophizing. Participants were 38 school children and 1 of their parents. Children completed a cold pressor pain task (CPT) twice, first when told that no one was observing (alone condition) and subsequently when told that they were being observed by their parent (parent‐present condition). A 3‐minute parent–child interaction occurred between the 2 CPT immersions, allowing measurement of parental attention to their child’s pain (ie, parental pain‐attending talk vs non‐pain‐attending talk). Findings showed that child pain catastrophizing moderated the impact of parental presence upon facial displays of pain. Specifically, low‐catastrophizing children expressed more pain in the presence of their parent, whereas high‐catastrophizing children showed equally pronounced pain expression when alone or in the presence of a parent. Furthermore, children’s catastrophizing moderated the impact of parental attention upon facial displays and self‐reports of pain; higher levels of parental nonpain talk were associated with increased facial expression and self‐reports of pain among high‐catastrophizing children; for low‐catastrophizing children, facial and self‐report of pain was independent of parental attention to pain. The findings are discussed in terms of possible mechanisms that may drive and maintain pain expression in high‐catastrophizing children, as well as potential limitations of traditional theories in explaining pediatric pain expression. The impact of parental presence and parental attention to the child’s pain upon the child’s pain expression is moderated by the child’s catastrophizing about pain.

Attentional processing of other’s facial display of pain: An eye tracking study

&NA; Initial attention allocation and attentional maintenance to facial expressions of pain is dependent upon intensity of facial pain expressiveness and observers’ pain intensity and catastrophizing. &NA; The present study investigated the role of observer pain catastrophizing and personal pain experience as possible moderators of attention to varying levels of facial pain expression in others. Eye movements were recorded as a direct and continuous index of attention allocation in a sample of 35 undergraduate students while viewing slides presenting picture pairs consisting of a neutral face combined with either a low, moderate, or high expressive pain face. Initial orienting of attention was measured as latency and duration of first fixation to 1 of 2 target images (i.e., neutral face vs pain face). Attentional maintenance was measured by gaze duration. With respect to initial orienting to pain, findings indicated that participants reporting low catastrophizing directed their attention more quickly to pain faces than to neutral faces, with fixation becoming increasingly faster with increasing levels of facial pain expression. In comparison, participants reporting high levels of catastrophizing showed decreased tendency to initially orient to pain faces, fixating equally quickly on neutral and pain faces. Duration of the first fixation revealed no significant effects. With respect to attentional maintenance, participants reporting high catastrophizing and pain intensity demonstrated significantly longer gaze duration for all face types (neutral and pain expression), relative to low catastrophizing counterparts. Finally, independent of catastrophizing, higher reported pain intensity contributed to decreased attentional maintenance to pain faces vs neutral faces. Theoretical implications and further research directions are discussed.

Children’s selective attention to pain and avoidance behaviour: The role of child and parental catastrophizing about pain

Summary Children’s selective attention to pain and its impact upon child avoidance behaviour is differentially sensitive to specific dimensions of child and parental catastrophizing. Abstract The present study investigated selective attention to pain in children, its implications for child avoidance behaviour, and the moderating role of dimensions comprising child and parental catastrophizing about pain (ie, rumination, magnification, and helplessness). Participants were 59 children (31 boys) aged 10‐16 years and one of their parents (41 mothers). Children performed a dot‐probe task in which child facial pain displays of varying pain expressiveness were presented. Child avoidance behaviour was indexed by child pain tolerance during a cold‐pressor task. Children and parents completed measures of child and parent pain catastrophizing, respectively. Findings indicated that both the nature of child selective attention to pain and the impact of selective attention upon child avoidance behaviour were differentially sensitive to specific dimensions of child and parental catastrophizing. Specifically, findings showed greater tendency to shift attention away from pain faces (ie, attentional avoidance) among children reporting greater pain magnification. A similar pattern was observed in terms of parental characteristics, such that children increasingly shifted attention away from pain with increasing levels of parental rumination and helplessness. Furthermore, child attentional avoidance was associated with greater avoidance behaviour (ie, lower pain tolerance) among children reporting high levels of pain magnification and those whose parents reported greater rumination about pain. The current findings corroborate catastrophizing as a multidimensional construct that may differentially impact outcomes and attest to the importance of assessing both child and parental characteristics in relation to child pain‐related attention and avoidance behaviour. Further research directions are discussed.

Perceived injustice after traumatic injury: Associations with pain, psychological distress, and quality of life outcomes 12 months after injury.

OBJECTIVE There is growing recognition that individuals who experience traumatic injuries perceive themselves as victims of injustice and that elevated levels of perceived injustice are associated with problematic physical and psychological outcomes. To date, research regarding injustice perception and injury outcomes has been restricted to a small number of musculoskeletal pain conditions. No research to date has examined the potential impact of perceived injustice among individuals admitted for trauma care. METHOD As part of this cross-sectional study, individuals (n = 155) admitted to a Level-1 trauma center completed measures of perceived injustice, pain, depression, posttraumatic stress, and health related (physical and mental/emotional) quality of life (HRQoL) outcomes 12 months after trauma admission. RESULTS Bivariate analyses revealed significant associations between perceived injustice and demographic variables (education, income, race, and age) as well as injury-related variables (type of injury and length of hospital stay). Perceived injustice was correlated with greater pain intensity, depression, and PTSD symptoms, as well as poorer physical and mental HRQoL. Controlling for relevant demographic and injury-related variables, perceived injustice accounted for unique variance in pain intensity, depression severity, the presence and intensity of PTSD symptoms, mental HRQoL, and was marginally significant for physical HRQoL. CONCLUSIONS This is the first study to examine perceived injustice in a trauma sample. Results support the presence of injustice perception in this group and its associations with pain and quality of life outcomes. Additional research is suggested to explore the impact of perceived injustice on recovery outcomes among individuals who have sustained traumatic injury.

Impact of parental catastrophizing and contextual threat on parents' emotional and behavioral responses to their child's pain.

Summary Heightened contextual threat induces elevated levels of parental psychophysiological distress in response to child pain, and is associated with more pain‐attending talk in catastrophizing parents. Abstract Limited research has addressed processes underlying parents’ empathic responses to their child’s pain. The present study investigated the effects of parental catastrophizing, threatening information about the child’s pain, and child pain expression upon parental emotional and behavioral responses to their child’s pain. A total of 56 school children participated in a heat pain task consisting of 48 trials while being observed by 1 of their parents. Trials were preceded by a blue or yellow circle, signaling possible pain stimulation (i.e., pain signal) or no pain stimulation (i.e., safety signal). Parents received either neutral or threatening information regarding the heat stimulus. Parents’ negative emotional responses when anticipating their child’s pain were assessed using psychophysiological measures— i.e., fear‐potentiated startle and corrugator EMG activity. Parental behavioral response to their child’s pain (i.e., pain attending talk) was assessed during a 3‐minute parent–child interaction that followed the pain task. The Child Facial Coding System (CFCS) was used to assess children’s facial pain expression during the pain task. Results indicated that receiving threatening information was associated with a stronger parental corrugator EMG activity during pain signals in comparison with safety signals. The same pattern was found for parental fear‐potentiated startle reflex, particularly when the child’s facial pain expression was high. In addition, parents who reported high levels of catastrophizing thought about their child’s pain engaged, in comparison with low‐catastrophizing parents, in more pain‐attending talk when they received threatening information. The findings are discussed in the context of affective‐motivational theories of pain.