"What we know is that depression is certainly a lot more likely if you have diabetes," says Susan Guzman, senior psychologist at the Behavioral Diabetes Institute in San Diego. "Is it the blood sugars that cause it? Is there a genetic component? We don't know."
In a review of 42 different studies, researchers in St. Louis, Mo., found that people with diabetes were twice as likely to be depressed as people without the disease, and women were at greater risk than men.
Guzman believes it is probably some combination of psychological and physical factors. Cultural, spiritual, and situational stressors may play a role as well.
"Diabetes gives people a lot of opportunities to feel like a failure," she says. "That really triggers depressive thinking."
More complications, more depression
Yet depression, while common in diabetes, is not normal, and there are things people can do to treat it. "We call it a biopsychosocial disease or condition, and usually treatment involves work in each of those areas," says Guzman.
People with diabetes and depression have a greater mortality risk than people the same age who have either one of those conditions alone, underscoring the need for treatment.
In fact, researchers in Pennsylvania recently reported that depressed, older adults with diabetes who received more resources for depression treatment were half as likely to die over a five-year period versus diabetics who didn't receive that level of care.