Pain and psychological factors in Huntington’s disease and Parkinson’s disease

Background: Chronic pain is a common aspect of many neurological conditions and often causes psychological distress. A scoping literature search revealed research was lacking in the area of Huntington’s disease (HD) and pain, therefore the empirical work focused on providing data on prevalence of pain and psychological predictors of pain in HD. There was insufficient research on HD and pain to form the basis of a review, however there was a body of literature on Parkinson’s disease (PD). The review focused on the relationship between pain and depression in people with PD. A critical appraisal of the experience of conducting the review and empirical work formed the final part of the thesis. Literature review: Fourteen articles were identified and reviewed in depth. Half of the studies, representing approximately three quarters of the participants in total, found a significant relationship between pain and depression in PD, with increased pain associated with increased depression. There was reasonable evidence to support an association between the severity of depression and the severity of pain in people with PD, although further research was recommended. Empirical report: A data-mining study was undertaken using data from 1474 participants of the European Huntington’s Disease Network (EHDN) REGISTRY study to examine the prevalence of pain in HD and to identify, using ordinal regression analysis, which psychological factors predicted severity of pain in people with HD. The prevalence of pain in HD was found to be 41%. Pain severity in HD was predicted by anxiety, depression and irritability. Caregivers and health professionals should consider the possibility that people with HD might be experiencing pain, particularly if there are signs of anxiety, depression or irritability. Recommendations were made for further research and limitations were discussed. Critical appraisal: The research process, methodology and main learning points were considered.