B. Hastie

Ethnic identity predicts experimental pain sensitivity in African Americans and Hispanics.

Abstract The aim of this study was to examine experimental pain sensitivity in three ethnic groups, African Americans, Hispanic Americans and non‐Hispanic White Americans, and to determine whether ethnic identity is differentially associated with pain sensitivity across ethnic groups. Participants included sixty‐three African American, sixty‐one Hispanic and eighty‐two non‐Hispanic white participants who were assessed using three experimental pain measures: thermal, cold‐pressor and ischemic. Participants’ ethnic identity was assessed using the Multi‐group Ethnic Identity Measure (MEIM). Ethnic group differences in pain responses were observed, with African American and Hispanic subjects showing lower cold and heat pain tolerances than non‐Hispanic White Americans. In addition, pain range (i.e. tolerance‐threshold) was computed for heat, cold and ischemic pain, and the two minority groups again had lower values compared to non‐Hispanic White Americans. Ethnic identity was associated with pain range only for African American and Hispanic groups. Statistically controlling for ethnic identity rendered some of the group differences in pain range non‐significant. These findings indicate that ethnic identity is associated with pain sensitivity in ethnic minority groups, and may partially mediate group differences in pain perception. The results of the present investigation provide evidence of ethnic group differences in responses to experimental pain across multiple noxious stimuli, with both minority groups exhibiting greater sensitivity to laboratory evoked pain compared to non‐Hispanic White Americans.

Cluster analysis of multiple experimental pain modalities.

&NA; Identifying individual differences in pain is an important topic; however, little is known regarding patterns of responses across various experimental pain modalities. This study evaluated subgroups emerging from multiple experimental pain measures. One hundred and eighty‐eight individuals (59.0% female) completed several psychological instruments and underwent ischemic, pressure, and thermal pain assessments. Thirteen separate pain measures were obtained by using three experimental pain modalities with several parameters tested within each modality. The pain ratings and scores were submitted to factor analysis that identified four pain factors from which Pain Sensitivity Index (PSI) scores were computed: heat pain (HP), pressure pain (PP), ischemic pain (IP), and temporal summation of heat pain (TS). Cluster analyses of PSI scores revealed four distinct clusters. The first cluster demonstrated high overall pain sensitivity, the second cluster revealed high TS, the third cluster showed particular insensitivity to IP and low sensitivity across pain modalities except PP, and the fourth cluster demonstrated low sensitivity to PP. Significant correlations were found between psychological measures and Index scores and those differed by sex. Cluster membership was associated with demographic variables of ethnicity and sex as well as specific psychosocial variables, although cluster differences were only partially explained by such factors. These analyses revealed that groups respond differently across varied pain stimuli, and this was not related solely to demographic or psychosocial factors. These findings highlight the need for future investigation to identify patterns of responses across different pain modalities in order to more accurately characterize individual differences in responses to experimental pain.

Sex-related psychological predictors of baseline pain perception and analgesic responses to pentazocine

Sex differences in pain perception and analgesic responses have garnered increasing attention in recent years. We examined the association of psychological factors to baseline pain perception and pentazocine analgesia among 49 healthy women and 39 men. Subjects completed psychological questionnaires measuring positive and negative affect as well as catastrophizing. Subsequently, responses to experimental pain were assessed before and after double-blind administration of intravenous pentazocine (0.5mg/kg). In correlational analyses, positive affect predicted lower pain sensitivity among men but not women. Negative affect predicted lower baseline pain tolerances among both sexes but predicted poorer analgesia only among men. Catastrophizing was associated with greater pain sensitivity and less analgesia more consistently in men than women. Regression models revealed that positive affect predicted lower overall pain sensitivity and catastrophizing predicted poorer overall analgesic responses among men, while no significant predictors of overall pain or analgesia emerged for women. Moreover, positive affect and catastrophizing were negatively and positively correlated, respectively, with side effects from the medication, but only among men. These findings indicate sex-dependent associations of psychological factors with baseline pain perception, analgesic responses, and medication side effects.

Ethnicity Interacts with the OPRM1 Gene in Experimental Pain Sensitivity

Summary Quantitative sensory testing in 3 ethnic groups and genotyping the A118G SNP of OPRM1 showed ethnicity‐dependent interactions with experimental pain sensitivity, independent of sex. Abstract Robust interindividual variation in pain sensitivity has been observed, and recent evidence suggests that some of the variability may be genetically mediated. Our previous data revealed significantly higher pressure pain thresholds among individuals possessing the minor G allele of the A118G SNP of the mu‐opioid receptor gene (OPRM1) compared with those with 2 consensus alleles. Moreover, ethnic differences in pain sensitivity have been widely reported. Yet, little is known about the potential interactive associations of ethnicity and genotype with pain perception. This study aimed to identify ethnic differences in OPRM1 allelic associations with experimental pain responses. A total of 247 healthy young adults from three ethnic groups (81 African Americans; 79 non‐white Hispanics; and 87 non‐Hispanic whites) underwent multiple experimental pain modalities (thermal, pressure, ischemic, cold pressor). Few African Americans (7.4%) expressed the rare allele of OPRM1 compared to non‐Hispanic whites and Hispanics (28.7% vs. 27.8%, respectively). Across the entire sample, OPRM1 genotype did not significantly affect pain sensitivity. However, analysis in each ethnic group separately revealed significant genotype effects for most pain modalities among non‐Hispanic‐whites (P < .05) but not Hispanics or African Americans. The G allele was associated with decreased pain sensitivity among whites only; a trend in the opposite direction emerged in Hispanics. The reasons for this dichotomy are unclear; they may involve ethnic differences in haplotypic structure, or A118G may be a tag‐SNP linked to other functional polymorphisms. These findings demonstrate an ethnicity‐dependent association of OPRM1 genotype with pain sensitivity. Additional research is warranted to uncover the mechanisms influencing these relationships.

Individual Differences in Opioid Efficacy for Chronic Noncancer Pain

ObjectiveOver a decade ago, Jamison noted the lack of studies that identify patient profiles or specific groups that might be best suited for opioid treatment of chronic noncancer pain. MethodsThis paper reviews the studies that provide evidence for individual differences in opioid analgesia for chronic noncancer pain. ResultsWhat we have found is that few investigations have addressed these important aspects of pain treatment. The most consistent finding is that depression and anxiety are associated with increased risk for drug abuse and decreased opioid efficacy. DiscussionThe question remains whether the psychologic disorders antedated the pain condition or whether the experience of chronic pain exerts psychologic pressures that cause changes in behavior and psychologic processes. Additionally, the overall pattern suggests that younger age is predictive of opioid abuse and greater opioid efficacy. We also present a brief review of biologic mechanisms that support individual differences on opioid analgesia.

Cognitive-affective and somatic side effects of morphine and pentazocine: side-effect profiles in healthy adults.

OBJECTIVE The side effects of opioids have been widely investigated, but it is unknown whether the subjective effects of mu agonists and mixed action opioids produce similar symptom profiles. This study examined the structure and predictive validity of somatic and cognitive/affective side-effect profiles of morphine and pentazocine using the Somatic Side Effects Questionnaire and the Cognitive and Affective Side Effects Questionnaire. DESIGN The subjects were 122 female and 90 male healthy volunteers that received an intravenous bolus administration of either 0.08 mg/kg of morphine or 0.5 mg/kg pentazocine. Pre- and post-drug experimental pain testing was also performed. Exploratory and confirmatory factor analysis resulted in similar factor structures for both drugs. RESULTS The most frequently reported side effects across both drugs involved feeling relaxed, sedation, and feeling in control. At equianalgesic doses, pentazocine had greater aversive side effects than morphine, whereas morphine was more associated with feelings of control and euphoria. For both drugs, females reported greater frequency of negative side effects than males. Using cluster analysis, we identified similar symptom profiles for each drug. These drug-related side-effect profiles were linked with analgesic responses. Specifically, groups that had a more positive side-effect profile experienced the greatest analgesic effect based on changes in ischemic pain sensitivity. CONCLUSIONS These findings have implications for decisions regarding opioid management of acute, chronic, and malignant pain conditions.

Partnerships Between Pediatric Palliative Care and Psychiatry

Children with life-threatening illnesses and their families may face physical, emotional, psychosocial, and spiritual challenges throughout the childrens course of illness. Pediatric palliative care is designed to meet such challenges. Given the psychosocial and emotional needs of children and their families it is clear that psychiatrists can, and do, play a role in delivering pediatric palliative care. In this article the partnership between pediatric palliative care and psychiatry is explored. The authors present an overview of pediatric palliative care followed by a summary of some of the roles for psychiatry. Two innovative pediatric palliative care programs that psychiatrists may or may not be aware of are described. Finally, some challenges that are faced in further developing this partnership and suggestions for future research are discussed.

Partnerships between pediatric palliative care and psychiatry.

Children with life-threatening illnesses and their families may face physical, emotional, psychosocial, and spiritual challenges throughout the childrens course of illness. Pediatric palliative care is designed to meet such challenges. Given the psychosocial and emotional needs of children and their families it is clear that psychiatrists can, and do, play a role in delivering pediatric palliative care. In this article the partnership between pediatric palliative care and psychiatry is explored. The authors present an overview of pediatric palliative care followed by a summary of some of the roles for psychiatry. Two innovative pediatric palliative care programs that psychiatrists may or may not be aware of are described. Finally, some challenges that are faced in further developing this partnership and suggestions for future research are discussed.