The Course of Psychological Distress and Determinants of Adjustment Following Diagnosis of Rheumatoid Arthritis
Norton, Samuel James
Chronic physical illnesses, such as rheumatoid arthritis (RA), that are painful and disabling not only impact on a person’s ability to complete normal daily activities (e.g. dressing, bathing, walking etc.) but may also have a negative impact on psychological well-being. Although a large number of prospective observational studies have examined psychological well-being in RA, none has used appropriate statistical techniques to examine variability in change over time at the individual level. The overarching aim of this dissertation is to use advanced quantitative methods to examine how psychological well-being in RA changes over the course of the disease; and to identify demographic, clinical and psychosocial factors that influence how the disease affects psychological well-being. This aim is addressed via a programme of research with three objectives: (i) to describe patterns of change in psychological well-being during the RA disease course; (ii) to quantify the association between psychological well-being and somatic symptoms; and (iii) to investigate the impact of illness cognitions and coping on psychological well-being. The programme of research consists mainly of analysis of a subsample of data collected as part of the Early RA Study (ERAS, N = 784), an ongoing observational study of RA patients followed prospectively from first presentation to a rheumatologist. A major problem relating to the assessment of psychological distress in individuals with chronic physical illness is the overlapping symptomatology with depression. An examination of the factorial validity of the Hospital Anxiety and Depression Scale (HADS), in the ERAS cohort, indicated the presence of a bifactor structure. Specifically, a general distress factor along with orthogonal (autonomic) anxiety and (anhedonic) depression factors was found to provide the optimal empirical explanation of the covariance in item responses. Further analysis, revealed that responses to one of the depression items were biased by disease severity. However, the magnitude of this bias was negligible, confirming the suitability of this tool in RA populations. For the ERAS cohort, general psychological distress was observed to reduce rapidly early in the course of the disease, stabilising after around two to three-years. However, further analysis suggested that subgroups with distinct longitudinal patterns of distress were present within the sample. Confirming observations in other disease groups, four distinct longitudinal patterns of distress were identified: resilient, chronic distress, delayed distress and recovered. Interestingly, changes in distress were related to self-reported somatic symptoms but not serological markers of disease activity. Building on these findings, analyses that jointly modelled changes in psychological distress with changes in the common somatic symptoms of pain and functional limitation revealed strong cross-sectional and longitudinal associations. This extends the findings of previous research by showing the importance of considering the impact of the disease course on the underlying trajectory of distress. Due to the lack of psychosocial data available in the ERAS cohort a further prospective study, involving 230 RA patients, was conducted to examine the influence of illness cognitions and coping on the affect of the disease on psychological well-being over a period of 6-months. Coping was not found to be related to changes in psychological well-being. Analysis revealed two groupings of patients with similar patterns of illness cognitions that were labelled adapters and non-adapters. Furthermore, cognitions concerning the attribution of symptoms to RA and the perceived personal consequences of their condition were related to changes in psychological distress, even after controlling for demographic and clinical characteristics; and there was some indication that a higher reported level of understanding of their condition was related to increased future positive outlook. In conclusion, the findings of this programme of research highlight the need for the early identification and treatment of RA, not only to slow the progression of the disease but also to maintain or improve psychological well-being. Early treatment is currently focused on pharmaceutical interventions. A tailored psychosomatic approach to treatment involving the skills of a wide range of health professionals, such as nurses, physiotherapists, occupational therapists and psychologists is likely to improve outcomes in RA.