Depression and diabetes
Depressive disorders are 2-6 times as common in those with diabetes, as compared with the non-diabetic population, and up to 40% experience depressive symptoms. Potential explanations include the burden of the condition and its social consequences, plus a number of factors predisposing to both disorders. These include overactivity of the hypothalamic-pituitary-adrenal (HPA) axis, tissue hypoxia, genetic factors and autoimmune processes. Depression has a negative impact upon the ability of patients to manage their own condition, and is associated with a 2-3 fold increase in cardiovascular morbidity, a 5-fold mortality and a greatly increased risk of microvascular complications. Depressive symptoms tend to precede the onset of type 2 diabetes, and constitute a risk factor for the disease. The observation of increased HPA activity in depressive disease dates back to the 1960s, and has suggested a possible endocrine basis for the disorder.