"Patients with diabetes experience distress and a great many negative feelings at the time of diagnosis," said Martha Funnell, a nurse at the Michigan Diabetes Research and Training Center and the Juvenile Diabetes Research Foundation Center for the Study of the Complications in Diabetes. "These feelings remain prevalent over the years with diabetes, and the majority of health professionals never address these issues."
Type 2 diabetes is, by no means, an easy diagnosis to face. Treatment of the disease requires a lifelong commitment to blood-sugar monitoring, constant attention to lifestyle and eating habits, and sometimes even daily insulin injections.
Funnell added that the act of treating the diabetes forces patients to come face-to-face with the reality of living with a chronic, life-altering disease.
"Another factor is that untreated diabetes is easier to ignore or to consider 'no big deal,' but initiating treatment triggers the understanding that it is serious, results in horrible complications, will likely shorten their life spans, and that they will now have a chronic disease for the rest of their lives," Funnell explained.
But some experts say a more important predictor of depression is whether the patient develops one of the many complications, such as eye disease, erectile dysfunction, kidney disease or failure, nerve damage, or even heart disease or stroke.
"I think this most important limitation of this study ... is the lack of controls for diabetes complications," said Richard Rubin, professor of medicine and pediatrics at the Johns Hopkins University School of Medicine. Rubin added that, in one of his own studies, which was published in Diabetes Care in 1997, it was suggested that the development of one of these complications significantly increases a patient's risk for depression.
While depression isn't commonly listed as a complication of diabetes, this study isn't the first to find that people struggling to keep their diabetes under control are often also struggling with depression.
The connection between diabetes and depression was first documented in the late 1600s by the English physician Thomas Willis, who said that "long-term sorrow" seemed to "generate" diabetes in some people.
A study published in the journal Diabetes Care in 2004 found that about 25 percent of diabetes patients suffer from a lifetime-long bout of serious depression. This prevalence rate is three times higher in the diabetes population than the general population.
Another study, published in Diabetes Care in 2000, also suggested that treatment of depression may improve a diabetes patient's control of blood sugar levels.
But experts still don't know which comes first -- the diabetes or the depression.
In a separate analysis of this study, doctors found that people with depression were slightly more likely to develop diabetes. However, many experts say this is probably because depressed people have less healthy lifestyle habits, and not because their depression is a direct trigger for diabetes.
Psychology experts say that it is very common for people who are diagnosed with a chronic disease such as diabetes to struggle with depression. Such individuals must relearn how to live their lives based on a complex system of dietary and medical interventions, and they are usually forced to alter their lifestyle, work, or school schedules.