What’s the Link Between Diabetes and Mental Illness?

Growing research suggests a link between diabetes and mental illness. While not everyone living with a mental illness develops diabetes, nor does everyone living with diabetes develop a mental illness, when one is present, the risk of developing the other increases. Diabetes and mental illness are potential risk factors for each other. This overview will help you gain insight into the link between diabetes and mental illness.

The Link Between Diabetes and Mental Illness: Which Mental Illnesses are Connected?

Thus far, a connection has been discovered between specific types of mental illness and Types 1 and 2 diabetes. These include:

• Mood disorders, especially major depressive disorder (see "What are the Effects of Diabetes on Mood Disorders? ")
• Anxiety disorders (see "Diabetes and Anxiety: There’s Plenty to Be Anxious About")
• Psychotic disorders, especially schizophrenia 
• Substance use disorders
• Eating disorders

Thus far, studies are less conclusive for eating disorders and substance use disorders and diabetes than they are for the others; therefore, let’s look at depression, anxiety, and schizophrenia and their link to diabetes.

The Connection Between Diabetes and Depression

People with one of these conditions, depression or diabetes, are at a heightened risk of developing the other ("Diabetes and Depression: Two Difficult Conditions to Manage"). According to one study, “the risk of developing depression is 50-100% higher among patients with diabetes compared to that of the general population” (Balhara, 2011).

Additionally, people with diabetes who do develop depression experience depression differently than those with depression but not diabetes. For reasons yet unknown, diabetes seems to cause episodes of depression that

• Last longer
• Recur more often

When someone has both serious illnesses, complications of both conditions worsen, mortality rates increase, and healthcare costs soar.

The Link Between Anxiety Disorders and Diabetes

Anxiety disorders are prevalent in the general population, and they’re even more so among people with diabetes. The two types of anxiety disorders that have the strongest link to diabetes are generalized anxiety disorder (GAD) and phobias.

GAD alone is three times higher among people with diabetes than it is in the non-diabetes population (Balhara, 2011). Perhaps understandably, specific phobias are related to diabetes: needle phobia, injection phobia, and the phobia of hypoglycemic episodes (dangerous drops in blood sugar levels).

People with fear of, or anxiety about, diabetes treatment tend to avoid doing what they need to do to stay healthy. Further, there can be confusion between the symptoms of anxiety and the symptoms of hypoglycemia. If someone dismisses the sweating, agitation, shakiness, irregular heartbeat, and confusion of a drop in blood sugar with anxiety and therefore doesn’t treat hypoglycemia properly, the consequences can be dire.

The Connection Between Schizophrenia and Diabetes

The link between diabetes and the mental illness schizophrenia has become well-known; perhaps because the numbers are relatively high. A condition called impaired glucose tolerance occurs when the body begins to have difficulty using insulin to move blood sugar (glucose) into cells for use as energy. It’s a form of hyperglycemia (high blood sugar) that is a precursor to diabetes. Approximately 30% of people with schizophrenia have impaired glucose tolerance. Further, someone with schizophrenia has a risk of developing type 2 diabetes that is double, triple, or even quadruple that of the general population.

Now that researchers are confident that diabetes and mental disorders are connected, the question that lingers is why. A few plausible explanations have emerged.

Reasons Diabetes and Mental Illness are Linked

Diabetes and mental illness can occur as separate conditions with little to do with each other; however, when someone does have both, the likelihood seems high that there is a relationship between them. It’s believed that certain factors cause one illness to lead to the development of another. Possible explanations for the link between diabetes and mental illness include:

• Genetic predisposition
• Physiological connection (happenings in the body like chronic inflammation, presence of stress hormones, or neurotransmitter problems)
• Lifestyle factors (inactivity, poor diet, obesity, smoking, improper treatment of or uncontrolled diabetes or mental illness)
• Psychiatric medication (many medications cause weight gain and/or impaired glycemia control)

Important Take-Aways from the Research

We can all benefit from what researchers are discovering. Crucial diabetes and mental illness factors to keep in mind include:

• The co-occurrence of mental illness and diabetes can lead to poor treatment adherence, increased healthcare costs, more hospitalizations, missed work and school, and overall lessened quality of life.
• Both diabetes and mental illness are treatable. There is hope.
• Now that we know that there’s a link, treatment will improve. It’s been shown that treating the conditions together is more successful than treating them separately.
• Diet, exercise, living an active lifestyle, and adhering to treatment help diabetes and mental illness.

The fact that diabetes and mental illness are linked can be shocking, but the news isn’t bad. Being aware of the connection will help you create and follow a comprehensive treatment plan ("Diabetes and Mental Health: How One Affects the Other "). You just might stop the development of either diabetes or mental illness, but if you do have both, you can live well despite the challenges.

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