Researchers have long understood there is a strong association between diabetes and depression. But new research presented at the American Diabetes Association's 74th Scientific Sessions shows that symptoms of depression in people with type 2 diabetes can be significantly reduced through interventions for "diabetes distress," suggesting that much of what is being labeled as depression may not be a co-morbid psychiatric disorder after all, but rather a reaction to living with a stressful, complex disease that is often difficult to manage.
A second study, of patients with type 1 diabetes, emphasizes the potential importance of treating depressive symptoms regardless of their cause: It found that the greater depressive symptoms a patient reported, the higher that person's mortality risk.
Diabetes distress v. depression
"Because depression is measured with scales that are symptom-based and not tied to cause, in many cases these symptoms may actually reflect the distress that people are having about their diabetes, and not a clinical diagnosis of depression," said lead author Lawrence Fisher, PhD, ABPP, Professor of Family and Community Medicine at the University of California, San Francisco.
Fisher and his team developed measures of diabetes-specific distress that reflect whether a person had been feeling worried about a variety of problems associated with living with their diabetes, such as hypoglycemia. They also asked patients to fill out the Patient Health Questionnaire to measure depressive symptoms. Those who reported high levels of distress and high levels of depressive symptoms were assigned one of three interventions, all of which were designed to reduce the distress associated with managing diabetes, rather than symptoms of depression.
One group took part in an online diabetes self-management program. A second participated in the online program, and received individual assistance to problem solve issues related to their diabetes distress. A third was provided with personalized health risk information and then sent educational material about diabetes through the mail. All groups received personal phone calls during the course of the project.
All three interventions significantly reduced distress as well as depressive symptoms over a 12-month period, and patients maintained those reductions over the course of the study. Overall, 84 percent of those scoring above 10 on the PHQ8 (maximum 27, with 10 being moderate depression) reduced their levels of depression to below 10 following the interventions, Fisher said. Reductions were evenly distributed for all three interventions.
"What's important about this," said Fisher, "is that many of the depressive symptoms reported by people with type 2 diabetes are really related to their diabetes, and don't have to be considered psychopathology. So they can be addressed as part of the spectrum of the experience of diabetes and dealt with by their diabetes care team."
Depressive symptoms associated with higher mortality
A second, unrelated study that analyzed data from a cohort of people with type 1 diabetes in the Pittsburgh area, the Pittsburgh Epidemiology of Diabetes Complications study (EDC), showed why it is so important to recognize depressive symptoms in people living with diabetes: Those who exhibit the highest level of depressive symptoms are most likely to die prematurely.
In this study, the Beck Depression Inventory was used to measure depressive symptoms such as low mood, losing interest in doing things, loss of appetite, feeling worthless and having suicidal tendencies. Participants in the study had been diagnosed with diabetes as children between 1950 and 1980, and were first studied in 1986. They are now in their 25th year of follow-up as part of a large, prospective cohort study.
"For every 1-point increase on the Beck Depression Inventory scale, participants showed a 4-percent increase in risk for mortality – after controlling for other factors that might increase the risk of death," said Cassie Fickley, the lead author who analyzed these data as part of her PhD degree.
"These data are very consistent with earlier findings from EDC which showed that greater depressive symptomatology predicted the incidence of heart disease in this cohort," said Trevor Orchard, MD, M.Med.Sci., FAHA, FACE, Professor of Epidemiology, Medicine and Pediatrics at the Graduate School of Public Health, University of Pittsburgh, and the EDC study principal investigator.
The earlier analysis was conducted by Cathy Lloyd, PhD, a co-author on the current paper, and currently a senior lecturer at the Open University in the UK. Lloyd noted that "the data are relatively unique as the consequences of depression in type 1 diabetes are an understudied area of research."