It's normal to feel down in the dumps sometimes. But when that feeling lingers every day for two weeks or more, it could be a sign of depression.

While most people with Type 1 or Type 2 diabetes do not have depression, studies show that people with diabetes have a greater risk of developing depression than those without the disease. In fact, people in the U.S. with diabetes are twice as likely as the average person to have depression, according to the National Institutes of Health.

Scientists do not know exactly why this is, and furthermore, it isn't clear whether diabetes increases the risk of depression or depression increases the risk of diabetes. Studies offer some possible, complex explanations for both cases.

Depression Influences Diet and Activity Levels

While depression is a mental disorder, it not only affects the brain, but also influences the entire body. The stress of managing diabetes on a daily basis can weigh heavily on someone's behavior. Some people may feel alone or sidelined from games with friends as a result of the blood glucose condition.

For those who deal with diabetes complications or have difficulty controlling blood sugar levels, frustration may be a natural consequence. This could lead to depression, which is a vicious cycle that causes problems with recommended diabetes self-care.

Also, physical inactivity—such as staying inside on sunny days or camping out in one's bedroom—is a common trait of depressive patients. Lack of energy might cause tasks like regular glucose monitoring to seem too difficult. What's more, not getting enough exercise is tied with obesity, which is a leading risk factor for Type 2 diabetes.

As you know, a healthy diet is a cornerstone of diabetes management. Certain individuals with depression may not feel like eating, which will affect blood sugar levels.

In the U.S., roughly 7 percent of adults ages 18 and older have depression, according to the National Institutes of Health.

The first step to treating depression is identifying it. Here are some symptoms:

• Loss of interest in daily activities
• Feelings of helplessness and hopelessness
• Appetite or weight changes (Drastic weight loss or weight gain such as a change of more than 5 percent of body weight in a month are telltale signs.)
• Sleep changes
• Anger or irritability
• Loss of energy (Your whole body may feel heavy, and even small tasks such as glucose monitoring are exhausting or take longer to complete.)
• Strong feelings of worthlessness or guilt
• Reckless behavior
• Concentration problems

To learn more about depression and diabetes:

Depression: The Hidden Diabetes Complication
Depression and Diabetes: 5 Steps Toward Better Mental Health
Depression or Diabetes Distress? Here’s Why It Matters and What You Can Do!