Joan Hester

Effects of mood on pain responses and pain tolerance: An experimental study in chronic back pain patients

&NA; Although chronic pain and depression commonly co‐occur, causal relationships have yet to be established. A reciprocal relationship, with depression increasing pain and vice versa, is most frequently suggested, but experimental evidence is needed to validate such a view. The most straightforward approach would be a demonstration that increasing or decreasing depressed mood predictably modifies pain responses. The current experiment tested whether experimentally induced depressed and happy mood have differential effects on pain ratings and tolerance in 55 patients suffering from chronic back pain. Participants were randomly assigned to depressed, neutral (control) or elated mood induction conditions. They completed a physically passive baseline task prior to receiving mood induction, then a clinically relevant physically active task (holding a heavy bag) to elicit pain responses and tolerance. Measures were taken immediately after the baseline task and immediately after the mood induction to assess the changes in mood, pain ratings and tolerance before and after the experimental manipulation. Results indicate that the induction of depressed mood resulted in significantly higher pain ratings at rest and lower pain tolerance, whilst induced happy mood resulted in significantly lower pain ratings at rest and greater pain tolerance. Correlations between changes in mood on the one hand and changes in pain response and pain tolerance on the other hand were consistent with these findings. It is concluded that, in chronic back pain patients, experimentally induced negative mood increases self‐reported pain and decreases tolerance for a pain‐relevant task, with positive mood having the opposite effect.

Pain-related insomnia versus primary insomnia: a comparison study of sleep pattern, psychological characteristics, and cognitive-behavioral processes.

Background:Recent applications of cognitive-behavior therapy for primary insomnia in the management of pain-related insomnia are based on the implicit assumption that the 2 types of insomnia share the same presentation and maintaining mechanisms. The objectives of this study were to compare the characteristics of patients who have pain-related insomnia with those reporting primary insomnia and to identify psychological factors that predict pain-related insomnia. Methods:Chronic pain patients with concomitant insomnia (n=137; Pain-related Insomnia Group) completed a selection of questionnaires that measure sleep patterns, psychological attributes, and cognitive-behavioral processes associated with the persistence of insomnia. Their responses were compared with those of primary insomnia patients (n=33; Primary Insomnia Group), using 3 sets of multivariate analyses of covariance that took account of demographic differences. Hierarchical regression analyses were performed to identify predictors of insomnia severity among the chronic pain patients. Results:The Pain-related Insomnia Group did not differ from the Primary Insomnia Group in their pattern and severity of sleep disturbance. The 2 groups were largely comparable in terms of their psychological characteristics, except that the Primary Insomnia Group was distinguishable from the Pain-related Insomnia Group by their greater tendency to worry. Patients in the Pain-related Insomnia Group reported levels of sleep-related anxiety and presleep somatic arousal that matched with those reported by patients in the Primary Insomnia Group. However, relative to patients in the Pain-related Insomnia Group, those in the Primary Insomnia Group reported more dysfunctional sleep beliefs and presleep cognitive arousal. In addition to pain intensity, depression, and presleep cognitive arousal were significant predictors of insomnia severity within the Pain-related Insomnia Group. Conclusions:There are more similarities than differences between the 2 types of insomnia. Besides pain, mood, and presleep, thought processes also seem to have a role in the manifestation of pain-related insomnia. It is suggested that hybrid treatments that seek to simultaneously address factors across these domains may represent more effective treatments than 1-dimensional interventions.

Mental defeat is linked to interference, distress and disability in chronic pain.

&NA; Mental defeat is a psychological construct that has recently been applied to characterize the experience of chronic pain. Elevated levels of mental defeat have been identified in patients with chronic pain, and while its presence distinguishes treatment seeking from non‐treatment seeking individuals, the link between mental defeat and disability in chronic pain is yet to be established. The current study investigated the extent to which mental defeat is associated with pain‐related interference, distress and disability. A total of 133 participants completed the Pain Self Perception Scale that assessed mental defeat in relation to pain. Moreover, the participants were asked to complete a set of questionnaires that measured pain interference, distress, disability and other demographic (age, body mass index), clinical (pain intensity) and psychological (catastrophizing, worry, rumination and health anxiety) predictors of disability. Mental defeat was found to be strongly correlated with pain interference, sleep disturbance, anxiety, depression, functional disability and psychosocial disability. These correlations remained significant even when pain intensity and demographic variables were partialled out. Relative to chronic pain patients with lower levels of mental defeat, those with higher levels of mental defeat reported greater degree of pain interference, distress and disability. In a series of regression analyses, mental defeat emerged as the strongest predictor of pain interference, depression and psychosocial disability, whereas catastrophizing was the best predictor of sleep interference, anxiety and functional disability. These findings suggest that mental defeat may be an important mediator of distress and disability in chronic pain. Theoretical and clinical implications are discussed.

Malignancy as a Possible Complication of Complex Regional Pain Syndrome: A Case Report

A synovial sarcoma presented in the knee of a young woman 20 years after the onset of pain which was attributed to complex regional pain syndrome (CRPS). Was this a chance occurrence, or could there be any link between the two conditions? Did the pain itself and the persistent inflammatory and immunological response to pain contribute to the development of malignancy, or could the malignancy have been present subclinically for many years and have contributed to the ongoing pain syndrome? This case report looks into the diagnosis of synovial sarcoma and CRPS and the relationship between the neurogenic inflammation seen in CRPS and that seen in malignancies. The diagnosis of CRPS is a diagnosis of exclusion. Constant vigilance of patients with this unpleasant condition is necessary.

Competing interests and the British Pain Society

The British Pain Society has a clear policy that any competing interests should be declared in its publications. The guidelines on the use of opioids for persistent pain to which Allan and Wager refer were first published in 2004.1 They have …