Abstract
Painful diabetic neuropathy (PDN) affects 25-30% of people with diabetes. PDN is a debilitating condition and has significant impacts on the physical and mental wellbeing. Specifically, it is associated with poor quality of life, impaired sleep, physical disability and increased anxiety and depression. Pharmacological treatments for PDN have limited effectiveness and often intolerable side effects. Previous research suggested that psychological interventions may be beneficial for chronic pain, but only a few trials have been conducted specifically for people with PDN. Acceptance and Commitment Therapy (ACT) has growing evidence of its effectiveness for chronic pain. However, there is no study applying an ACT-based intervention to people with PDN. This thesis focuses on examining PDN within the framework of the psychological flexibility model and, relatedly, considering the potential usefulness of ACT for people with PDN. This thesis comprises of 3 studies.Study 1: A systematic review examining and summarising evidence from observational studies of psychosocial factors and treatment trials of psychological interventions conducted with populations of people with PDN. Results suggest that sleep, quality of life, anxiety and depression are the most studied variables, within the PDN literature, and each is consistently associated with pain intensity. While only three Randomised Controlled Trials included psychological treatments applied to this population, there were promising results for their effectiveness. Evidence from commonly studied variables in chronic pain, such as coping or pain beliefs, was lacking in PDN research. Due to the lack of research, a study examining theoretically based psychosocial factors was suggested.
Study 2: The second study in this set was a cross-sectional survey investigating the association between facets of psychological flexibility (acceptance of pain, committed action, cognitive fusion and self as a context), and distress and daily functioning in people with PDN. Overall, 225 participants with PDN were recruited from hospital diabetes outpatient clinics and online. Through correlation analyses, acceptance of pain is shown to be negatively correlated with pain intensity, pain distress, functional impairment, depression severity, and depression impact. Cognitive fusion correlated positively with pain intensity, functional impairment, depression severity, and depression impact. Committed action correlated negatively with functional impairment, depression severity and depression impact. In regression analyses, the combination of the four variables representing psychological flexibility accounted for significant variance in all equations except in the case of pain distress. The results of this study suggest that psychological flexibility may play a meaningful role in the context of PDN, and psychological treatment focused on psychological flexibility was indicated.
Study 3: The third study tested the feasibility of ACT among individuals with PDN in the UK. This was a single-cohort study of an online ACT treatment package, which was originally developed for chronic pain populations. Primary feasibility outcomes were recruitment, retention and treatment completion rates. Secondary outcomes were within-groups effects on pain outcomes and psychological flexibility. Process and outcome variables were measured at pre-treatment and 3 months post-treatment. The treatment completion rate was 40% for the ACT online treatment with all participants completing the follow-up questionnaires. Treatment completers demonstrated significantly lower levels of pain intensity and distress, depression and functional impairment and higher levels of committed action over time compared with non-completers. However, online ACT for people with PDN, seems to have limited feasibility and changes to the protocol, treatment content, and delivery may be needed before further testing in a larger feasibility study.
Certainly, further developments in treatments for people with PDN are needed. In turn, this will require greater attention to PDN by clinical researchers conducting studies of psychosocial processes linked to clinical outcomes. The set of studies described here produced preliminary evidence for a particular set of psychosocial factors and application of a psychological intervention for people with PDN, based on the psychological flexibility model. It provided some support for the feasibility of ACT, including suggestive evidence around clinical outcomes. Further study of a modified ACT-based intervention in the healthcare context of the UK is suggested.
| Date of Award | 1 Jul 2020 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Lance McCracken (Supervisor), Kirsty Winkley (Supervisor), Emma Godfrey (Supervisor) & Whitney Scott (Supervisor) |