Depression in Diabetes: Have We Been Missing Something Important?

An extensive literature has developed to suggest that depression is more common in patients with diabetes than in the general population (1) and is associated with chronic hyperglycemia (2), risk for diabetes complications (3), and mortality (4). Although the causal linkages among these relationships have not been demonstrated, their consistency has led to calls for intensive efforts to identify and treat clinical depression in patients with diabetes, with the reasonable presumption that this will contribute to better diabetes outcomes. Recent studies, however, suggest a more complicated picture and cast doubt on this presumption. Although research has suggested that the prevalence of clinical depression, or major depressive disorder (MDD), among adults with diabetes may be two to three times greater than among community adults (1), recent studies—which have used structured clinical interviews, the gold standard in the diagnosis of MDD—suggest that it is only about 60% more common (5). More importantly, diabetes-related distress, or significant negative emotional reactions to the diagnosis of diabetes, threat of complications, self-management demands, unresponsive providers, and/or unsupportive interpersonal relationships, has been found to be far more common, more chronic, and more closely related to diabetes self-care and glycemic control than MDD (5–7). Symptoms of depression, such as depressed mood, diminished interest, loss of energy, and concentration difficulties, that are elevated but do not meet severity criteria for MDD (referred to here as depressive symptoms) are also quite common among patients with diabetes and are associated with poor self-care (8). Furthermore, increased risk of complications and early mortality is not limited to those with MDD but also extends to those with elevated depressive symptoms, even when these elevations are quite modest (4). This suggests an incremental relationship between the severity of depressive symptoms and poorer diabetes outcomes rather than an effect of MDD per …