Human Studies

Among 170 adults with sickle cell disease, we evaluated chronic pain impact and disability prevalence, assessed age and gender differences, and identified psychosocial predictors of chronic pain intensity and disability. Most participants had a high level of disability. Chronic pain intensity and disability were significantly associated with pain catastrophizing and chronic pain self-efficacy, and worsened with age. Further research is needed to confirm study findings and develop interventions, including palliative care approaches that address catastrophizing and disability, particularly for young women and middle-aged adults with sickle cell disease. Moreover, consistent clinical assessment of chronic pain and psychosocial health should be implemented.

Current guidelines for addressing opioid cessation in the context of chronic pain management recommend that opioids be discontinued if the risks outweigh the benefits. However, few studies have focused on understanding opioid cessation from the perspective of individuals with chronic pain. This mixed-method study included 49 former opioid users with chronic pain and used quantitative survey data and qualitative focus group data to identify themes pertaining to former opioid user's experience before, during, and after opioid cessation. Participants described several reasons for wanting to stop opioids including lack of efficacy, impact on quality of life, and concerns about addiction. Barriers to cessation included concerns about inadequate pain management and concerns about the impact of stopping opioids on mood. After opioid cessation, the sample was mixed regarding the benefit of cessation. Half of the former opioid users reported their pain to be better or the same after stopping opioids; however, 47% of the sample reported feeling worse pain since stopping their opioids. As the pendulum swings from pain control to drug control, we must ensure that the response to the opioid epidemic does not cause harm to individuals with chronic pain. Novel opioid cessation interventions are needed in combination with methods of addressing individual challenges and barriers to adequate pain relief including access to and provision of nonopioid alternatives for pain management.

Childhood trauma has been linked to neuropathic pain in noncancer populations, but its relationship with cancer treatment-related neuropathic pain is unknown.

This study examined psychosocial pain treatment moderation in a secondary analysis of a trial that compared cognitive therapy (CT), mindfulness-meditation (MM), and mindfulness-based cognitive therapy (MBCT) for chronic low back pain (CLBP). The Limit, Activate and Enhance (LA&E) model of moderation provided a framework for testing a priori hypotheses. Adult participants (N=69) with CLBP completed a pre-treatment assessment of hypothesized moderators: pain catastrophizing, brain state as assessed by electroencephalogram, mindful observing, and non-reactivity. Outcomes were pain interference, characteristic pain intensity, physical function, and depression, assessed at pre- and post-treatment. Moderation analyses found significant interaction effects, specifically: (1) higher and lower baseline pain catastrophizing was associated with greater improvement in pain intensity in MM and MBCT, respectively; (2) higher baseline theta power was associated with greater improvement in depression in MBCT and interfered with response to CT; (3) lower baseline non-reactivity was associated with greater improvement in physical function in MM while higher non-reactivity was associated with greater improvement in MBCT. The findings support the possibility that different patients are more or less likely to benefit from various treatments. Theory-driven moderation research has the capacity to inform the development of patient-treatment matching algorithms to optimize outcome. Perspective: This study presents preliminary findings from theory-driven tests of the moderators of mindfulness meditation, cognitive therapy and mindfulness-based cognitive therapy for chronic low back pain. The results of such analyses may inform the understanding of for whom various evidence-based psychosocial pain treatments may engender the most meaningful benefits.

Chronic low back pain (CLBP) is a major cause of global disability and improving management is essential. Acceptance and Commitment Therapy (ACT) is a promising treatment for chronic pain but has not been modified for physical therapy. This randomized controlled trial (RCT) compared physical therapy informed by Acceptance and Commitment Therapy (PACT) against standard care physical therapy for patients with CLBP. Patients with CLBP (duration ≥12 weeks, mean 3 years) were recruited from physical therapy clinics in four UK public hospitals. The Roland-Morris Disability Questionnaire (RMDQ) at 3 months' post randomization was the primary outcome. 248 participants (59% female, mean age=48) were recruited and 219 (88•3%) completed measures at 3 and/or 12 months' follow-up. At 3 months, PACT participants reported better outcomes for disability (RMDQ mean difference =1•07, p=0•037, 95%CI -2•08 to -0•07, d=0•2), Patient Specific Functioning (p=0.008), SF12 physical health (p=0.032), and treatment credibility (p<0.001). At 12 months' follow-up there were no significant differences between groups. PACT was acceptable to patients and clinicians and feasible to deliver. Physical therapists incorporated psychological principles successfully and treatment was delivered with high (≥80%) fidelity. Our results may inform the management of CLBP, with potential benefits for patients, health care providers and society. PERSPECTIVE: Psychologically informed physical therapy has great potential but there are challenges in implementation. The training and support included in the PACT trial enabled the intervention to be delivered as planned. This successfully reduced disability in the short but not long term. Findings could inform physical therapists' treatment of CLBP.

Avoidance is considered key in the development of chronic pain. However, little is known about how avoidance behaviour subsequently affects pain-related fear and pain. We investigated this using a robotic arm reaching avoidance task to investigate this. In a between-subjects design both Experimental Group (n=30) and Yoked Control Group (n=30) participants perform either of three movement trajectories (T1-T3) to reach a target location. During acquisition, only participants of the Experimental Group could partially or fully avoid a painful electrocutaneous stimulus by choosing the intermediate trajectory (T2; 50% reinforcement) or the longest trajectory (T3; 0% reinforcement) versus the shortest trajectory (T1: 100% reinforcement). After acquisition, contingencies changed (all trajectories 50% reinforced), and the acquired avoidance behaviour no longer effectively prevented pain from occurring. The Yoked Control Group received the same reinforcement schedule as the Experimental Group irrespective of their behaviour. When avoidance behaviour became ineffective for the Experimental Group, pain-related fear increased for the previously safe(r) trajectories (T2 and T3) and remained the same for T1, whereas pain threshold and tolerance declined. For the Yoked Group, pain-related fear increased for all trajectories. The Experimental Group persisted in emitting avoidance behaviour following the contingency change, albeit at a lower frequency than during acquisition. PERSPECTIVE: Results indicate participants become more afraid of and sensitive to pain, when previously acquired avoidance is no longer effective. Also, participants continue to show avoidance behaviour despite it being not adaptive anymore. These findings suggest that ineffective avoidance may play role in the maintenance and development of chronic pain.