This study fits into the field of behavioural medicine which tries to better understand the mind-body connection. That is, why does what we think and feel affect our bodies in ways which can cause us to become unwell? Quantitative research has repeatedly shown that depression is associated with the onset and progression of multiple different physical illnesses. However, we are still trying to understand why this is the case. We propose that the experience of depression in the physically ill may partly explain this, however this has yet to be addressed in previous research. Qualitative methods involve asking participants about their experiences of living with disease. In this study we propose to ask persons with 4 different diagnoses (depression only, depression comorbid with: coronary heart disease, arthritis or type 2 diabetes) in order to look for similarities and differences in individual experiences. We are particularly interested to know whether the symptoms of depression present themselves differently across the different physical illness groups and the timeline and course of depressive symptoms in relation to an individual’s physical illness symptoms. Such questions are possible to answer using quantitative methods using sophisticated statistical techniques, however such approaches strip away the context of the diagnosis which might help researchers to understand the finer details of this important issue. Three physical illness groups have been selected since they are all prevalent in the UK primary care setting and have all been associated with depression in cross-sectional and prospective analyses. These illness are: arthritis, coronary heart disease and type 2 diabetes. These three diseases have also been selected since they have all been shown to have involve inflammatory processes, which is one hypothesised mechanism linking depression to physical illness. Importantly each of the three diseases manifest themselves with different symptoms, physical limitations and treatment regimes, making cross-group comparisons possible. Using face-to-face interviews of up to 60 primary care patients we aim to better delineate the similarities and differences in the experience of depression between those patients with a psychiatric diagnosis but who are otherwise physically healthy in comparison to those with depression and a comorbid physical illness. This research will help us to better understand the experience of depression in physical illness, helping to inform studies on the early identification and treatment of depression in primary care.The purpose of this research is to understand more about biosocial pathways in health by studying depression symptoms and how they relate to physical illnesses such as diabetes, heart disease and cancer. We already know that people suffering from these diseases are more likely to experience symptoms of depression than those without them. We also know that people who experience depression symptoms are more likely to develop a physical illness later in life. However, as yet, we are not sure why depression symptoms and physical illnesses are related in these ways. I am particularly interested in the biological pathways linking depression symptoms and physical illnesses. These pathways include things like how our bodies respond to stress and how well our immune system works. For example, I am interested in a substance called cortisol which is released by the body when we feel stressed or sad. I am also interested in part of the immune system which is responsible for levels of inflammation. Research has shown that cortisol and inflammation do not work as well as they should in people who have depression symptoms or a physical illness. Therefore, I am interested in finding out whether changes in these things can explain the link between depression symptoms and physical illness morbidity in people who suffer from a variety of different physical illnesses. My research fits in well with the ESRC's priorities for this award: biosocial research and secondary analyses of longitudinal data. I am proposing to conduct biosocial research since I am planning to study the biology of a problem that society is facing. In addition, I intend to use longitudinal data that has already been collected, but has not yet been used to answer the questions I am interested in. I will use two main methods to analyse my data: quantitative analyses of existing data and qualitative analyses of a new study. I will use data from studies such as Whitehall II, the English Longitudinal Study of Ageing (ELSA), and Midlife in the United States study (MIDUS) among others. Using these datasets will allow me to partly answer my questions using statistical analyses. In addition, I will conduct a qualitative study in order to speak to individuals living with either a mental or physical illness about their experiences of depression symptoms. This will enable me to explore how people think, feel and cope with their illnesses and their mood. This research is important for a number of reasons. First of all, research has shown that people who have depression symptoms and a physical illness are likely to experience more symptoms of their physical illness than those without depression symptoms. In other words, they are more likely to feel sicker than those without depression symptoms. This links to the second important reason. If we understand why people with physical illness also get depression symptoms then we can improve our treatment of these individuals. At the moment, our current treatment options are not always very effective. So, not only do these people suffer more symptoms of their illness, their depression symptoms do not always go away with treatment. If we can improve treatment, then we can reduce suffering. Another reason that this research is important is the scale of the problem. Currently a lot of people with a physical illness also experience depression symptoms. Sadly, research has shown that a lot of these patients do not get identified by doctors as needing extra help. I plan to raise awareness of this issue during the course of my fellowship by ensuring I reach out to policymakers, health professionals and the public.

Face to face qualitative interviews with primary care patients with depression.