Background and aims: This interdisciplinary thesis was designed to deepen understanding of the co-morbidity of anxiety and depression with chronic diseases of the digestive tract, and inflammatory bowel disease (IBD) in particular. The first part of the thesis aimed to explore the prevalence of psychological problems in IBD compared to irritable bowel syndrome (IBS) and chronic hepatitis C (HCV) groups. It also explored the relationship between the number of co-morbid functional gastrointestinal disorders and the severity of psychological problems in IBD and IBS. It also aimed to determine whether there is a relationship between psychological problems and the response to standard medical treatment/physical outcomes in patients with IBD, IBS and HCV. Furthermore, it aimed to explore whether disclosure of the psychological status of depressed and/or anxious IBD patients to their gastroenterologists influences doctors’ behaviour and affects patients’ responses to treatment/physical outcomes. The second part of the thesis aimed to investigate the potential role of antidepressants in IBD and to determine the feasibility of future randomised controlled trials on the role of antidepressants in IBD. Methods: Overall, a cohort of 139 outpatients (64 IBD, 41 HCV, and 34 IBS) and 18 gastroenterologists participated in the six studies comprising this thesis. A mixed methods design was applied. Two cross-sectional studies, an observational cohort prospective management study, a randomised controlled trial, a systematic review and an exploratory interview study were conducted. Differences between the groups for continuous variables were assesed with one way analysis of variance (ANOVA) and independent samples ttests. Differences in categorical variables were assessed with contingency tables with the Chi-Square test and the Fisher’s Exact Test. Propsective analyses were conducted with repeated measures ANOVA, logistic regression and Poisson regression. Qualitative data were analysed using content analysis. Results: Overall, 42% of participants were anxious and 19% were depressed. Participants with HCV had higher levels of psychological impairment compared with the IBS, the IBD group and the general population (p<0.05). Those IBD participants with fewer co-morbid functional disorders had better physical quality of life than participants with a greater number of these disorders (p=0.025). Moreover, depression/anxiety at baseline did not explain medical outcomes after 12 months in this cohort of patients with chronic diseases of the digestive tract. Doctors’ knowledge of patients’ psychological status was found to have no impact on IBD patients’ outcomes after 12 months. However, interestingly, the level of anxiety in IBD participants significantly dropped between the baseline and nine months indicating a possible benefit from participating in the study. In the literature review, insufficient evidence was found to conclude that antidepressants are efficacious for treatment of psychological co-morbidities or somatic complaints in IBD. However, the qualitative interview study indicated a potential positive impact of treatment with antidepressants on coping with disease symptoms and general wellbeing in patients with IBD. Conclusion: The thesis confirms that there is a significant burden of psychological co-morbidity in patients with chronic gastroenterological diseases. Interdisciplinary approaches to the management of these diseases are therefore warranted in Australian gastroenterology clinics. Anxiety targeted interventions and research in this setting are urgently needed, especially with respect to patients with HCV. Larger studies exploring the gastroenterologists’ role in treatment of co-morbid psychological problems in their patients are recommended. Longer prospective studies on homogenous samples of patients are also needed to clarify the nature of the relationship between psychological problems and relapse of somatic symptoms. Finally, randomised controlled trials exploring the efficacy of antidepressants in IBD are warranted. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1321006 / Thesis (Ph.D.) -- University of Adelaide, School of Population Health and Clinical Practice, 2008

Background and aims: This interdisciplinary thesis was designed to deepen understanding of the co-morbidity of anxiety and depression with chronic diseases of the digestive tract, and inflammatory bowel disease (IBD) in particular. The first part of the thesis aimed to explore the prevalence of psychological problems in IBD compared to irritable bowel syndrome (IBS) and chronic hepatitis C (HCV) groups. It also explored the relationship between the number of co-morbid functional gastrointestinal disorders and the severity of psychological problems in IBD and IBS. It also aimed to determine whether there is a relationship between psychological problems and the response to standard medical treatment/physical outcomes in patients with IBD, IBS and HCV. Furthermore, it aimed to explore whether disclosure of the psychological status of depressed and/or anxious IBD patients to their gastroenterologists influences doctors’ behaviour and affects patients’ responses to treatment/physical outcomes. The second part of the thesis aimed to investigate the potential role of antidepressants in IBD and to determine the feasibility of future randomised controlled trials on the role of antidepressants in IBD. Methods: Overall, a cohort of 139 outpatients (64 IBD, 41 HCV, and 34 IBS) and 18 gastroenterologists participated in the six studies comprising this thesis. A mixed methods design was applied. Two cross-sectional studies, an observational cohort prospective management study, a randomised controlled trial, a systematic review and an exploratory interview study were conducted. Differences between the groups for continuous variables were assesed with one way analysis of variance (ANOVA) and independent samples ttests. Differences in categorical variables were assessed with contingency tables with the Chi-Square test and the Fisher’s Exact Test. Propsective analyses were conducted with repeated measures ANOVA, logistic regression and Poisson regression. Qualitative data were analysed using content analysis. Results: Overall, 42% of participants were anxious and 19% were depressed. Participants with HCV had higher levels of psychological impairment compared with the IBS, the IBD group and the general population (p<0.05). Those IBD participants with fewer co-morbid functional disorders had better physical quality of life than participants with a greater number of these disorders (p=0.025). Moreover, depression/anxiety at baseline did not explain medical outcomes after 12 months in this cohort of patients with chronic diseases of the digestive tract. Doctors’ knowledge of patients’ psychological status was found to have no impact on IBD patients’ outcomes after 12 months. However, interestingly, the level of anxiety in IBD participants significantly dropped between the baseline and nine months indicating a possible benefit from participating in the study. In the literature review, insufficient evidence was found to conclude that antidepressants are efficacious for treatment of psychological co-morbidities or somatic complaints in IBD. However, the qualitative interview study indicated a potential positive impact of treatment with antidepressants on coping with disease symptoms and general wellbeing in patients with IBD. Conclusion: The thesis confirms that there is a significant burden of psychological co-morbidity in patients with chronic gastroenterological diseases. Interdisciplinary approaches to the management of these diseases are therefore warranted in Australian gastroenterology clinics. Anxiety targeted interventions and research in this setting are urgently needed, especially with respect to patients with HCV. Larger studies exploring the gastroenterologists’ role in treatment of co-morbid psychological problems in their patients are recommended. Longer prospective studies on homogenous samples of patients are also needed to clarify the nature of the relationship between psychological problems and relapse of somatic symptoms. Finally, randomised controlled trials exploring the efficacy of antidepressants in IBD are warranted. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1321006 / Thesis (Ph.D.) -- University of Adelaide, School of Population Health and Clinical Practice, 2008