Pain
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Recent studies have provided consistent evidence for a genetic influence on chronic widespread pain (CWP). The aim of this study was to investigate (1) the etiological structure underlying CWP by examining the covariation between CWP and psychological comorbidities and psychoaffective correlates and (2) the decomposition of the covariation into genetic and environmental components. A total of 3266 female twins (mean age 56.6 years) were subject to multivariate analyses. ⋯ The results show that the clustering of CWP and depression is due to a common, highly heritable, underlying latent trait. In addition, we found evidence that CWP, anxiety, emotional instability, and emotional intelligence are influenced by different underlying latent traits sharing the same genetic and nonshared environmental factors. This is the first study to reveal the structure and relative importance of genetic and environmental influences on complex etiological mechanisms of CWP and its correlates.
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It is believed that patients' expectancies about the effectiveness of treatment influence their treatment outcomes, but the working mechanism is rarely studied in patients with low back pain. Theoretical models suggest that adherence to treatment may be an important pathway. The aim of this study was to assess the mediating role of adherence to treatment in the relationship between expectancies and the outcomes of recovery and pain intensity in patients with acute low back pain. ⋯ A total of 1573 participants were included in current analyses. There was a small but highly significant relationship between expectancies and outcomes; 3.3% of the relationship between expectancies and recovery and 14.2% of the relationship between expectancies and pain intensity were mediated by adherence to treatment. This study does not convincingly support the theory that adherence is a key pathway in the relationship between treatment outcome expectancies and recovery and pain intensity in this acute low back pain population.
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Morphine and other opioid analgesics are potent pain-relieving agents routinely used for pain management in patients with cancer. However, these drugs have recently been associated with a worse relapse-free survival in patients with surgical cancer, thus suggesting that morphine adversely affects cancer progression and relapse. ⋯ Our studies further demonstrate that morphine, administered in the presence or absence of surgery-induced tissue damage, neither facilitates de novo metastatic dissemination nor promotes outgrowth of minimal residual disease after surgery. Together, these findings indicate that opioid analgesics can be used safely for perioperative pain management in patients with cancer and emphasize that current standards of "good clinical practice" should be maintained.