From the DDD Conceptual Issues Working Group, courtesy of Ed Fisher

i. The relationship between diabetes and depression is complex and bidirectional.

1. "Complex" in that multiple areas of influence are involved: biological, clinical, behavioral, social, cultural, and environmental.
2. "Bidirectional" in that there is evidence that depression may raise the likelihood of diabetes and, also, evidence that diabetes may raise the likelihood of depression.

ii. The prevalence of the co-occurrence of diabetes and depression and the many links between them raise the question of whether they are best understood as two separate, co-morbid disease entities. From the perspective of population approaches to prevention and management, for example, depression might be viewed as a normal component of clinical diabetes and diabetes might be viewed as a common feature of depression.

iii. In cardiovascular disease, the case is made that it is not so much any specific psychological problem but rather a broad set of negative emotions - anger, hostility, anxiety, depression, stress - that are problematic in terms of CVD etiology, course, morbidity, and mortality. The relationships between diabetes and depression, on the other hand, may be more specific than this. Nevertheless, prevention and management initiatives may consider the merits of focusing broadly on negative emotions or specifically on depression and diabetes.

iv. The burden of diabetes, depression and their co-occurrence make these issues of great public health significance.

v. The complexity of influences and relationships among diabetes and depression indicate the importance of broad approaches to prevention and management that address the environmental and behavioral as well as biological factors involved and that consider the contexts of individuals' lives as they shape the relationships between and relative importance of diabetes and depression.

From the Pathogenesis Working Group, courtesy of Alan Jacobson

i. Although there is a well-recognized association of depression with both type 1 and type 2 diabetes the pathogenesis of this co-morbidity is not understood and may well differ between the two types of diabetes.

ii. Structural and neuro-chemical changes induced by diabetes may contribute to the development of depression and associated cognitive disturbances in both types of diabetes.

iii. Obesity and insulin resistance themselves can induce changes in insulin receptors and in cytokines that may impact on brain function and structure and thereby lead to increased risk for both depression and type 2 diabetes.

iv. Notwithstanding diabetes-specific metabolic factors, the emotional stresses of diabetes can play a role in the development of depression, especially as complications develop and become increasingly symptomatic.

From the Epidemiology Working Group, courtesy of Cathy Lloyd

i. Current epidemiological evidence suggests that at least one third of people with diabetes suffer from clinically relevant depressive disorders. Furthermore, people with depressive disorders have an increased risk of developing diabetes.

ii. Depression can lead to poor self-care, affect glycaemic control and compromise quality of life. Indeed the prognosis of both diabetes and depression - in terms of severity of disease, complications, treatment resistance and mortality - as well as the costs to both the individual and society is worse for either disease when they are co-morbid than it is when they occur separately.

iii. In spite of the huge impact of co-morbid depression and diabetes on the individual and its importance as a public health problem, questions still remain as to the most appropriate ways of identifying and treating people suffering from depression.

From the Health Economics Working Group, courtesy of David McDaid

i. Flagging up the substantial costs of co-morbid diabetes and depression: indicating that they are high and wide-ranging and examples of this can be identified worldwide. Because, for example, depression increases a number of diabetes complications for a patient, the co-morbid condition increases costs by more than might be expected.

ii. Highlighting that the economic impact can be especially significant in the area of employment, because of absenteeism, low productivity when at work (presenteeism) and withdrawal from the labour market. This has consequences both for employers, governments (because of lost tax revenue - need to pay out benefits etc) and of course to the individuals themselves in terms of reduced incomes. Consequently, decisions to invest in better health care might generate their biggest economic pay-offs outside the health sector.

iii. There is a small body of evidence from high income countries to support the cost-effectiveness of interventions such as a collaborative care model for people with diabetes identified as having/or being at risk of depression. These evaluations demonstrate that proved outcomes can be achieved at a cost which would be seen as worth paying by society in high income countries.

iv. There is an urgent need to improve what we know about the cost effectiveness of interventions for people with diabetes at risk of depression in low and middle income country contexts, and in all settings on the economic benefits of actions to reduce the risk of diabetes in people with depression.

v. We might start to work on a simple and effective protocol to prove the cost-effectiveness of early identification and appropriate treatment of the morbid association of diabetes and depression.

From the Health Care Delivery Working Group, courtesy of Richard Roberts

i. Systems of care (how care is organized, delivered, and funded) likely have greater impact on the outcomes of those with depression and diabetes than does any one individual preventive or therapeutic strategy.

ii. We know remarkably little about the effects of different systems of care on those with depression and diabetes.

iii. Research to better understand the effects of systems of care is desperately needed, vitally important, and extremely challenging, given the multiple factors and their interplay that must be considered.

From the DDD Public Health Interventions Working Group

Content coming soon.

From the Treatment and Its Evaluation Working Group

Content coming soon.