Brian Poeschla

Self-immolation: Socioeconomic, cultural and psychiatric patterns

INTRODUCTION Self-immolation remains a significant contemporary problem. Its epidemiology and causes, and the intervention strategies these suggest vary significantly between higher- and lower-income countries. We summarize what is known about suicide by self-immolation in terms of its demographic and psychiatric risk factors, causes, local patterns and means employed, and points of possible intervention. METHODS We reviewed the literature for all published papers on self-immolation between 1973 and 2010. Epidemiologic and psychiatric risk factors and aspects of method, locale and timing of self-immolation were compared between higher- and lower-income countries. RESULTS In higher-income countries self-immolation tends to be rare and the majority of self-immolation patients are male. In lower-income countries, the incidence of self-immolation is much higher, and the majority of patients are female. Self-immolation was more frequently associated with a history of mental illness or substance abuse history in higher-income countries than in lower-income countries. CONCLUSION Reports in the literature of self-immolation divide most informatively into two groups according to the higher- or lower-income of the societies affected. This classification is not arbitrary, as it correlates with other measures of development, and the epidemiologic patterns revealed show distinct differences, suggesting differing causes and intervention strategies. Analytical studies are needed to distinguish associations from underlying causes and identify efficient points of intervention.

C-Reactive Protein and Pain Sensitivity: Findings from Female Twins

BackgroundSystemic inflammation and pain sensitivity may contribute to the development and maintenance of chronic pain conditions.PurposeWe examined the relationship between systemic inflammation as measured by C-reactive protein (CRP) and cold pain sensitivity in 198 female twins from the University of Washington Twin Registry. We also explored the potential role of familial factors in this relationship.MethodsLinear regression modeling with generalized estimating equations examined the overall and within-pair associations.ResultsHigher levels of CRP were associated with higher pain sensitivity ratings at pain threshold (p = 0.02) and tolerance (p = 0.03) after adjusting for age, body mass index, time to reach pain threshold or tolerance, and clinical pain status. The magnitude of the associations remained the same in within-pair analyses controlling for familial factors.ConclusionsThe link between CRP and pain sensitivity may be due to non-shared environmental factors. CRP and pain sensitivity can be examined as potential biomarkers for chronic pain and other inflammatory conditions.

Chronic Fatigue and Personality: A Twin Study of Causal Pathways and Shared Liabilities

BackgroundThe etiology of chronic fatigue syndrome (CFS) remains unknown. Personality traits influence well-being and may play a role in CFS and unexplained chronic fatigue.PurposeThis study aimed to examine the association of emotional instability and extraversion with chronic fatigue and CFS in a genetically informative sample.MethodsWe evaluated 245 twin pairs for two definitions of chronic fatigue. They completed the Neuroticism and Extraversion subscales of the NEO Five Factor Inventory. Using a co-twin control design, we examined the association between personality and chronic fatigue.ResultsHigher emotional instability was associated with both definitions of chronic fatigue and was confounded by shared genetics. Lower extraversion was also associated with both definitions of fatigue, but was not confounded by familial factors.ConclusionsBoth emotional instability and extraversion are related to chronic fatigue and CFS. Whereas emotional instability and chronic fatigue are linked by shared genetic mechanisms, the relationship with extraversion may be causal and bidirectional.

Serotonin syndrome associated with polypharmacy in the elderly

The increasing use of serotonergic agents, alone and in combination, across multiple disciplines, makes it likely that the prevalence of serotonin syndrome will rise. Caution should be used, especially in the elderly, to avoid unnecessary and potentially harmful polypharmacy. We describe a case of serotonin syndrome in a 79-year-old man taking mirtazapine, venlafaxine and quetiapine. As this case illustrates, serotonin syndrome can be caused by combinations of direct serotonin agonists (e.g., serotonergic antidepressants) and indirect serotonin agonists (e.g., atypical antipsychotics).

Salivary Cortisol and Cold Pain Sensitivity in Female Twins

BackgroundThere is a dearth of knowledge about the link between cortisol and pain sensitivity.PurposeWe examined the association of salivary cortisol with indices of cold pain sensitivity in 198 female twins and explored the role of familial confounding.MethodsThree-day saliva samples were collected for cortisol levels and a cold pressor test was used to collect pain ratings and time to threshold and tolerance. Linear regression modeling with generalized estimating equations examined the overall and within-pair associations.ResultsLower diurnal variation of cortisol was associated with higher pain ratings at threshold (p = 0.02) and tolerance (p < 0.01). The relationship of diurnal variation with pain ratings at threshold and tolerance was minimally influenced by familial factors (i.e., genetics and common environment).ConclusionsUnderstanding the genetic and non-genetic mechanisms underlying the link between HPA axis dysregulation and pain sensitivity may help to prevent chronic pain development and maintenance.

Clinical and evoked pain, personality traits, and emotional states: Can familial confounding explain the associations?

OBJECTIVES Pain is a complex phenomenon influenced by context and person-specific factors. Affective dimensions of pain involve both enduring personality traits and fleeting emotional states. We examined how personality traits and emotional states are linked with clinical and evoked pain in a twin sample. METHODS 99 female twin pairs were evaluated for clinical and evoked pain using the McGill Pain Questionnaire (MPQ) and dolorimetry, and completed the 120-item International Personality Item Pool (IPIP), the Positive and Negative Affect Scale (PANAS), and ratings of stress and mood. Using a co-twin control design we examined a) the relationship of personality traits and emotional states with clinical and evoked pain and b) whether genetics and common environment (i.e. familial factors) may account for the associations. RESULTS Neuroticism was associated with the sensory component of the MPQ; this relationship was not confounded by familial factors. None of the emotional state measures was associated with the MPQ. PANAS negative affect was associated with lower evoked pressure pain threshold and tolerance; these associations were confounded by familial factors. There were no associations between IPIP traits and evoked pain. CONCLUSIONS A relationship exists between neuroticism and clinical pain that is not confounded by familial factors. There is no similar relationship between negative emotional states and clinical pain. In contrast, the relationship between negative emotional states and evoked pain is strong while the relationship with enduring personality traits is weak. The relationship between negative emotional states and evoked pain appears to be non-causal and due to familial factors.

Dexamethasone-suppressed Salivary Cortisol and Pain Sensitivity in Female Twins

Objectives: Hypothalamic-pituitary-adrenal (HPA) axis dysregulation is associated with chronic pain. Studying pain sensitivity and the HPA axis could elucidate the role of stress in chronic pain development, which might be influenced by familial factors, including genes. Methods: Associations between pain sensitivity and salivary cortisol and familial confounding in these associations were examined in 88 female, community-based twin pairs (75% monozygotic, mean age 29 y). Cortisol was assessed after 0.25 mg dexamethasone (DEX), recovery from 0.25 mg DEX, and after 0.5 mg DEX. Cold pressor task (CPT) pain ratings were obtained at threshold and at tolerance. Conditioned pain modulation (CPM) was examined using thermal heat as the testing stimulus and hot water as the conditioning stimulus. Generalized estimating equation models were used and adjusted for baseline pain rating, age, and other relevant covariates. Results: After controlling for baseline cortisol, greater cortisol suppression following DEX administration and lower recovery cortisol levels were associated with higher pain ratings at tolerance during the CPT (Bs=−2.42 to −17.82; Ps=0.031 to<0.001) as well as with reduced CPM (Bs=−0.92 to −1.68; Ps=0.003 to 0.046). Interestingly, familial confounding was evident in the CPT and CPM during recovery from DEX administration, but not immediately following DEX administration. Discussion: These findings contribute to understanding possible mechanisms underlying chronic pain by demonstrating that HPA axis response to negative feedback is related to pain sensitivity.