Depression and Type 2 Diabetes

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History of depression increases risk of type 2 diabetes in younger adults, by L.C. Brown and colleagues. Diabetes Care 28:1063-1067, 2005.

What is the problem and what is known about it so far?

Depression is an illness that involves the body, mood, and thoughts. It affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. Without treatment, symptoms of depression can last for weeks, months, or years. The right treatment, however, can help most people who suffer from depression. More information about the symptoms, causes, and treatment of depression can be found at http://www.nimh.nih.gov/publicat/depression.cfm.

In recent years, many studies have shown that patients with diabetes are twice as likely to have depression than people without diabetes. However, it's not clear whether people who have a history of depression are more likely to get diabetes.

Why did the researchers do this particular study?

To see whether people who have a history of depression are more likely to get type 2 diabetes than people who don't have a history of depression.

Who was studied?

A total of 92,677 residents of Saskatchewan, Canada, who were eligible for prescription drug coverage and were older than 20 years of age.

How was the study done?

The researchers looked through the Saskatchewan Health databases to find information on people who were eligible for prescription drug coverage and were at least 20 years old between 1992 and 2000. They identified over 33,000 people who had type 2 diabetes, and they selected almost 60,000 people without diabetes to serve as a comparison group. They recorded when diabetes was diagnosed, as well as how many people had depression and how long they had depression. They then compared depression among people with diabetes and people without diabetes.

What did the researchers find?

People with newly diagnosed diabetes were 30% more likely to have had a history of depression than people without diabetes. This difference though was only found in people who were between 20 and 50 years of age. There was no difference in people who were older than 50 years.

What were the limitations of the study?

Some people may have symptoms of diabetes but don't seek medical treatment. This study had no way to account for people with undiagnosed diabetes.

Likewise, many people don't seek treatment for depression, and this study had no way to account for undiagnosed depression.

People who seek treatment for depression may be more likely to be checked for other conditions. If they have diabetes, there’s a greater chance that it will be diagnosed.

What are the implications of the study?

Young adults who have a history of depression are more likely to get type 2 diabetes than people who don't have a history of depression. More studies are needed to see how depression and type 2 diabetes are related.

FOR MORE INFORMATION

Depression

The prevalence of comorbid depression in adults with diabetes: a meta-analysis, by R.J. Anderson and colleagues. Diabetes Care 24:1069-1078, 2001.

101 Tips for Coping With Diabetes, by R. Rubin and colleagues ( Alexandria , Va. , ADA , 2003)