Diabetes Forecast

The Diabetes and Depression Connection

There’s a link between diabetes and depression—but it’s not what researchers initially thought

By Andrew Curry , ,


Nina Flores started feeling down about 17 years ago, not long after the birth of her first child. She had always been happy and outgoing, but now it was as if a gray cloud had descended and refused to lift. “Everyone expects you to smile, but you can’t,” she says. “You just feel sad, for no reason.”

As the years went by, Flores’s depression took a toll on her daily life and her family. She found it hard to get out of bed, let alone eat well and exercise. After nearly a decade, her doctor prescribed antidepressant medication, and soon she began to feel like her old self again. Last year, however, Flores was diagnosed with type 2 diabetes. Learning to manage it has taken a toll—and, she says, triggered another bout of depression. “It feels like the medication doesn’t work as well as it used to,” she says. “I get gray days more often than before [my diagnosis].

”Flores’s experience is in keeping with new research into the links between diabetes and depression. Researchers have known for decades that clinical depression is a common problem for people with both type 1 and type 2 diabetes, who suffer at similar rates. Much more than feeling sad once in a while, clinical depression is a long-lasting and more-crippling disorder that interferes with daily life and relationships. And it’s deeply interconnected with diabetes—so deeply that researchers now think it is a two-way relationship: People with diabetes are more likely to develop depression, and people with depression are more likely to develop diabetes.

The reason for the overlap between depression and diabetes once seemed obvious: Doctors figured people were simply depressed about their diabetes. The shock of a life-changing diagnosis, the burden of checking blood glucose throughout the day, the need to take multiple medications, and concern over the stigma associated with the disease all lowered people’s spirits and made them feel blue.

But new research suggests that the link between depression and diabetes may be more complex. People with clinical depression are up to 60 percent more likely to develop diabetes later in life. In a long-term study of people with type 2 diabetes, published in 2016 in Diabetes Care, participants reported long depressive episodes even before their diabetes diagnoses, suggesting that depression doesn’t hit only after diagnosis.

Such findings indicate that the idea of people being sad about their diabetes is not merely too simplistic—for many people, it may be wrong. Indiana University clinical psychologist Mary de Groot, PhD, says there’s an increasingly urgent effort to unravel the real reasons diabetes and depression often come together. The goal is to develop treatments that can address the specific needs of people with diabetes struggling with depression. Ultimately, some researchers hope to find ways to help people with depression delay the onset of and lessen the severity of type 2 diabetes.

Researchers and mental health care professionals are also working to raise awareness of the differences between clinical depression and what’s known as diabetes distress, a more fleeting feeling of frustration or stress connected to the daily burden of diabetes self-care and often referred to as diabetes burnout. The hope is that people with clinical depression can be identified and treated early. “We have been learning a lot in the last 25 years,” says de Groot, acting director of the Diabetes Translational Research Center at Indiana University. “It’s a high-priority item in the community.”

Connecting the Dots

Research shows that 1 in 4 people with diabetes will experience depression in their lifetime. New research suggests they’ll experience it differently than those who don’t have diabetes. Between 2006 and 2009, de Groot worked with patients in West Virginia and Ohio as part of an experiment into the effectiveness of exercise and counseling for people with type 2 diabetes. Part of the study, published in 2015 and 2016 in Diabetes Care, found that participants with diabetes and depression had periods of depressed mood that tended to last longer and happen more often than those without diabetes. “The average depressive episode is 22 weeks in the general population,” says de Groot. “In adults with type 2, the average duration was 92 weeks.”

In de Groot’s study, something else stood out: Participants who had experienced depression before they were diagnosed with diabetes spent the same amount of time depressed after their diabetes diagnosis as they had before. If the psychological toll of dealing with diabetes was causing depression, people would experience it more profoundly after their diagnosis. But that wasn’t the case. For de Groot, that was a strong sign that diabetes burnout was something different from the clinical depression participants in her study were experiencing.

That suggests a deeper, perhaps physiological or genetic connection between diabetes and depression. If researchers are able to untangle the diabetes–depression connection, they might be able to break the cycle. But so far, the links remain a mystery. “What are the mechanisms? That’s the million-dollar question,” says de Groot.

Potential Answers

Stress is one possible culprit. Over time, “fight-or-flight hormones” released in response to stressful situations can cause chemical changes in the brain that trigger depression. Stress can alter digestion and metabolism, and prompt unhealthy eating, adding to the risk of obesity and type 2 diabetes.

Another possibility is chronic inflammation. Under normal circumstances, inflammation is one way the body deals with infections. But in people with diabetes and depression, it can become an ever-present condition. The link has led some researchers to suggest that chronic inflammation might be a common cause for both conditions.

Other research suggests a link might lie in the way cells respond to stimuli, both in the brain and in the pancreas. “Clinicians and scientists are looking for a common basis,” says Agata Jurczyk, PhD, a cell biologist at the University of Massachusetts Medical School. “We’re interested in whether dysfunction at the cellular level can impact multiple organ systems.”

Neurotransmitters are chemicals that conduct signals from neuron to neuron in the brain. Preliminary research suggests some cases of depression are caused by a malfunction in the response to the neurotransmitters, which somewhat short-circuits the brain’s pleasure signals.

Beta cells in the pancreas produce insulin similar to how neurons make neurotransmitters. Might people who have trouble releasing neurotransmitters also have trouble secreting insulin? University of Massachusetts Medical School neuroscientist Ann Rittenhouse, PhD, is working with Jurczyk to find a way to test the theory. “Beta cells and neurons also have a similar secretion process,” says Rittenhouse. “It’s not surprising you might see diabetes and mental illness occuring in the same patients. So many of the proteins are used in the same way.”

Vicious Circle

Depression and diabetes are a particularly difficult combination because each condition reinforces the other. “When diabetes and depression go together, it contributes to greater functional disability and early mortality,” says de Groot. It’s a two-way street: Diabetes worsens the symptoms of depression, and depression makes it harder to take care of your diabetes. Dozens of studies have shown that depression is associated with missed medical appointments, poor diet, lack of exercise, and lack of attention to medication use and glucose monitoring. Any one of those oversights can increase blood glucose. That, in turn, “may contribute to depressive symptoms and consequently contribute to decreased adherence to self-care behaviors,” according to a study published in 2014 in the journal Current Diabetes Reports.

Case in point: When Flores was struggling with depression, she “didn’t worry that much about diet or exercise,” she says. Since her diabetes diagnosis, however, she’s turned things around, paying closer attention to healthful eating and exercise. “I’ve lost weight, and I’m more in tune with making sure I exercise,” she says. “It’s helped mentally, but the depression is still there.” She’s now working with her doctor to see if a different antidepressant might work better.

The Path Forward

Research shows that diet, exercise, support groups, therapy, and medication can all be effective treatments for depression. Most antidepressants work just as well in people with diabetes as in those without. “Often people feel like they’re in the weeds,” says Mark Heyman, PhD, CDE, a clinical psychologist who directs the Center for Diabetes and Mental Health in San Diego. “Medication can help them see the path forward.”

Perhaps just as important is moving beyond self-blame, which can prevent someone with diabetes from getting the help they need. “Depression happens,” de Groot says. “One of the key pieces to take away is that if you’re developing depression, it’s not a character flaw.”

Diabetes Distress

Psychologists draw a distinction between clinical depression and diabetes-related distress, or what some call diabetes burnout. Diabetes distress is the frustration and low feelings that the daily burdens of caring for diabetes can cause. It, too, is a common problem: 40 to 45 percent of people with diabetes will experience it in their lifetime.

“The overwhelming nature of managing diabetes can be hard to handle,” says Mark Heyman, PhD, CDE, a clinical psychologist who has type 1 diabetes. “With most conditions, you go to a doctor, take a pill, and go on and live your life. With diabetes, you’re making decisions on a daily basis.”

Some of the symptoms of high blood glucose, such as fatigue and difficulty concentrating, mimic depression. Those feelings are no less valid, but the way mental health professionals approach them may be different. “Some people experience depression that’s neurochemical,” says Heyman, who specializes in treating people with diabetes. “For most people, it’s really the situation. They have work challenges, family challenges, school challenges, and with diabetes on top of that, it can be overwhelming. The world can feel very small.”

Heyman tells his patients to start with modest steps. Rather than trying to fix everything at once, tackle things one step at a time. “Focusing on one goal is a lot more doable,” he says. “Today it’s healthy eating, tomorrow checking blood sugar.”

Symptoms To Look For

How do you know if you’re clinically depressed? Check for these signs:

  • Loss of pleasure
  • Changes to sleep patterns
  • Changes in appetite
  • Difficulty concentrating
  • Loss of energy
  • Guilt
  • Feelings of worthlessness
  • Sadness
  • Suicidal thoughts

“Whether you have type 1 or type 2, if you are noticing two or more weeks of symptoms of depression, it’s important to share that with your health care provider,” says Indiana University psychologist Mary de Groot, PhD. After your first conversation, keep your provider in the loop—especially if you’re taking an antidepressant, because the dosage may need to be adjusted over time. And different drugs may have different effects, raising or lowering blood glucose depending on the drug and the patient. “It’s important to keep the conversation going,” says de Groot.

Looking for Help?

Find a provider in your area by searching the American Diabetes Association’s list of mental health care providers who treat people with diabetes at professional.diabetes.org/mhp_listing.



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