Placebo treatment affects brain systems related to affective and cognitive processes, but not nociceptive pain.

Drug treatments for pain often do not outperform placebo, and a better understanding of placebo mechanisms is needed to improve treatment development and clinical practice. In a large-scale fMRI study (N = 392) with pre-registered analyses, we tested whether placebo analgesic treatment modulates nociceptive processes, and whether its effects generalize from conditioned to unconditioned pain modalities. Placebo treatment caused robust analgesia in conditioned thermal pain that generalized to unconditioned mechanical pain. However, placebo did not decrease pain-related fMRI activity in brain measures linked to nociceptive pain, including the Neurologic Pain Signature (NPS) and spinothalamic pathway regions, with strong support for null effects in Bayes Factor analyses. In addition, surprisingly, placebo increased activity in some spinothalamic regions for unconditioned mechanical pain. In contrast, placebo reduced activity in a neuromarker associated with higher-level contributions to pain, the Stimulus Intensity Independent Pain Signature (SIIPS), and affected activity in brain regions related to motivation and value, in both pain modalities. Individual differences in behavioral analgesia were correlated with neural changes in both modalities. Our results indicate that cognitive and affective processes primarily drive placebo analgesia, and show the potential of neuromarkers for separating treatment influences on nociception from influences on evaluative processes.

The effect of somatic pain and comorbid mental distress on oral health-related quality of life in orthodontic patients.

OBJECTIVES: The purpose of the present study was to evaluate the prevalence of somatic pain in orthodontic patients and determine whether somatic pain contributes to worsening oral health-related quality of life (OHRQoL) through the mediating effect of psychological discomfort. MATERIALS AND METHODS: Scale measurements and analyses were conducted on a cohort of 769 orthodontic outpatients, encompassing Patient Health Questionnaire-15-pain (PHQ-15-P), Hua-Xi Emotional-Distress Index (HEI), Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ), and Oral Health Impact Profile-14 (OHIP-14). RESULTS: Among the respondents, 56.3% (N = 433) reported somatic pain and 20.0% (N = 154) had mental discomfort based on PHQ-15-P and HEI scores. Patients with somatic pain symptoms had significantly higher scores of HEI and OHIP-14 (P < 0.001), and higher PHQ-15-P and HEI scores emerged as statistically significant predictors of lower OHIP-14 scores (P < 0.001). HEI scores which assessed anxiety and depression partially mediated the correlation between PHQ-15-P and OHIP-14 scores, of which anxiety accounted for 52.9% of the overall mediation effect, dominating the indirect effect. CONCLUSION: Orthodontic patients reporting somatic pains were at a significantly higher risk of worsening OHRQoL during treatment, and this adverse effect is partially mediated by anxiety and depression. CLINICAL RELEVANCE: Our findings highlight the necessity for the assessment of general health and mental well-being during orthodontic interventions. To prevent delays in treating general disorders and the potential failure of orthodontic treatments, we encourage increased attentiveness towards patients with somatic symptoms and consideration of the adverse effects of comorbid mental distress.

Central pain due to stroke: cognitive representation and coping according to gender / Dor central em acidente vascular encefálico: representação cognitiva e enfrentamento conforme o gênero

OBJECTIVE: To identify and compare perceptions of pain and how it is faced between men and women with central post-stroke pain. METHODS: The participants were 25 men and 25 women of minimum age 30 years-old and minimum schooling level of four years, presenting central post-stroke pain for at least three months. The instruments used were: Mini-Mental State Examination; structured interview for the Brief Psychiatric Scale; Survey of Sociodemographic and Clinical Data; Visual Analogue Scale (VAS); Ways of Coping with Problems Scale (WCPS) in Scale; Revised Illness Perception Questionnaire (IPQ-R); and Beck Depression Inventory (BDI). RESULTS: A significantly greater number of women used the coping strategy "Turn to spiritual and religious activities" in WCPS. They associated their emotional state with the cause of pain in IPQ-R. "Distraction of attention" was the strategy most used by the subjects. CONCLUSION: Women used spiritual and religious activities more as a coping strategy and perceived their emotional state as the cause of pain.

OBJETIVO: Identificar e comparar a percepção e o enfrentamento da dor entre homens e mulheres com dor central por acidente vascular cerebral (AVC). MÉTODOS: Participaram do estudo 25 homens e 25 mulheres com dor central por AVC há pelo menos três meses, maiores de 30 anos, escolaridade mínima de 4ª série. Os instrumentos utilizados foram: Mini-exame do Estado Mental; Entrevista Estruturada para Escala Psiquiátrica Breve; Inquérito de Dados Sociodemográficos e Clínicos; Escala Visual Analógica (EVA); Escala dos Modos de Enfrentamento de Problemas (EMEP); Questionário de Percepção da Doença Revisado (QPD-R) e Inventário de Depressão de Beck (IDB). RESULTADOS: Um número significativamente maior de mulheres revelou usar a estratégia de enfrentamento "Realizar atividades espirituais e religiosas" na EMEP e associou o estado emocional à causa de suas dores no QPD-R. "Distração da atenção" foi a estratégia mais utilizada pelos sujeitos. CONCLUSÃO: As mulheres utilizaram mais atividades espirituais e religiosas como estratégia de enfrentamento e perceberam mais o estado emocional como causa da dor.