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Schizophrenia and Diabetes

Medically Reviewed by Melinda Ratini, DO, MS on May 10, 2022

About 1 in 10 people in the U.S. have diabetes. Most of them have type 2 diabetes. This is when your cells don’t respond normally to insulin, a hormone your body makes. Insulin allows your cells to take in and use blood sugar. If your cells don’t respond to insulin like they should, your blood sugar will go up.

You might not think that a disease related to blood sugar would have anything to do with schizophrenia. But when you have schizophrenia, you’re even more likely than the average person to have type 2 diabetes and its related health risks. Studies suggest that diabetes is up to five times more common in people with schizophrenia compared to people without the condition. That means about 1 in 5 people with schizophrenia also have diabetes. It’s likely that this happens because of many different things.

Why Is Schizophrenia Linked to Diabetes?

First of all, people with schizophrenia often have other risk factors that would make anyone more likely to get diabetes. These include:

  • Obesity
  • High cholesterol or other blood lipids
  • High blood sugar
  • Smoking
  • Unhealthy diet
  • Too little exercise
  • Poor sleep
  • Stress

Why do these go along with schizophrenia? People with schizophrenia often don’t have a very active lifestyle. They may eat too few fruits and vegetables and too much fast food that’s high in sugar and fats. Studies have shown that people with schizophrenia are more likely than the average person to be overweight. There’s also evidence that people with schizophrenia are less likely to get moderate exercise. More vigorous exercise is even less likely when you’re in this group.

People with schizophrenia also tend to have differences in their sleeping patterns. Changes in your body’s internal clock might play into changes in your metabolism and raise your risk of diabetes.

Smoking also is a risk factor for type 2 diabetes. That’s important because people with schizophrenia are much more likely than other people to smoke. A lot of people with schizophrenia who smoke do so heavily.

When you put all these things together, it’s easy to see how people with schizophrenia as a group would be at greater risk for developing diabetes.

Schizophrenia, Diabetes, and Poverty

Schizophrenia and diabetes also have a common link. People with schizophrenia and other severe mental illnesses often face challenges in finding and keeping employment – a situation that in turn has a negative effect on mental health. They may find it harder to find quality housing and food, both of which raise the risk for diabetes. In addition, they often don’t get the care they need to manage their health conditions.

Diabetes and Your Schizophrenia Medicines

On top of those lifestyle factors, the medicines you take for schizophrenia may come with more risk for diabetes. It’s possible that some of these medicines make you more likely to gain weight. But some of these medicines might also cause more direct changes in your metabolism and blood sugar. These include:

  • Antipsychotics
  • Antidepressants
  • Mood stabilizers

The link between schizophrenia medications and diabetes risk may be even stronger for certain racial and ethnic groups. Several long-term studies, both large and small, found that both African American and Hispanic people with schizophrenia who took medications for the condition were more likely to develop diabetes than white people. But other studies have had different results. We need more research to fully understand how schizophrenia medications may affect racial and ethnic groups.

Ask your doctor about the side effects of the medicines you or a loved one are taking. Find out if they might come with more risk for diabetes and if there are steps you can take to make that less likely.

Could the Link From Schizophrenia to Diabetes Start Even Earlier?

Studies suggest that some of the same genes that make a person more likely to have schizophrenia might also increase the risk for diabetes. Another study also found signs of pre-diabetes or diabetes risk in people at the time of their first episode of symptoms leading to a schizophrenia diagnosis.

In other words, people who develop schizophrenia may already have changes in their blood sugar that increase their risk for diabetes. So people with schizophrenia may already have more risk for diabetes, even before medicines and lifestyle factors related to this condition come into play.

Complications of Diabetes When You Have Schizophrenia

Diabetes comes with a high risk for serious health problems. It makes heart disease or a stroke more likely. It also can cause damage to your nerves, kidneys, and eyes. The heart risks related to diabetes may explain why people with schizophrenia don’t live as long as other people do. Life expectancy when you have schizophrenia is about 65 years.

Estimates suggest that diabetes and heart disease may lead people with schizophrenia to die about 15 years earlier on average, if not more. This happens mostly because of physical illnesses that people with schizophrenia more often have. It’s not typically because of suicide or the mental illness itself.

Diabetes Care When You Have Schizophrenia

Given these risks for diabetes and other health problems, it’s a good idea for doctors to screen people with schizophrenia for diabetes and treat them for it if their blood sugar is high. But people with the disorder too often don’t get the treatment they need. This could be another reason that people with schizophrenia don’t live as long as they should.

If you or a loved one is being treated for schizophrenia, ask if the medicines for it could cause diabetes or make it worse. If you have diabetes or early signs that you may get diabetes, your doctor should take this into account. You may be able to lower your risk for diabetes and other health problems that go with it by taking metformin or other medicines.

Your doctor may be able to help you with healthy eating, an exercise program, or other changes to help prevent diabetes. If you or your loved one with schizophrenia already have it, they can work with you to treat it.

Show Sources

SOURCES:

Centers for Disease Control and Prevention: “Type 2 Diabetes,” “Smoking and Diabetes.”

Psychiatriki: “Schizophrenia and type 2 diabetes mellitus.”

International Journal of Endocrinology: “An Overview of Diabetes Management in Schizophrenia Patients: Office Based Strategies for Primary Care Practitioners and Endocrinologists.”

JAMA Psychiatry: “Impaired Glucose Homeostasis in First-Episode Schizophrenia A Systematic Review and Meta-analysis.”

Mayo Clinic: “Diabetes.”

BMC Psychiatry: “Quality of diabetes care in patients with schizophrenia: a case-control study in Qatar.”

Journal of General Internal Medicine: “Diabetes and Cardiovascular Care Among People with Severe Mental Illness: A Literature Review.”

World Bank: “Poverty and Health.”

BMC Psychiatry: “Mental health affects future employment as job loss affects mental health: findings from a longitudinal population study.”

American Journal of Public Health: “Disparities in Diabetes: The Nexus of Race, Poverty, and Place.”

University of California San Francisco: “Diabetes Added to High Risks for People with Severe Mental Illness.”

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