Depression and Diabetes: a Dangerous Combination

By: Diana Barnes-Brown for Diabetes1

For years, many doctors and researchers have believed that depression might be a complication of diabetes. This belief was based on anecdotal evidence from patients, accounts from other practitioners, and connections visible in other studies conducted over the past two decades. 

Know What to Look For (Note that some of these symptoms overlap or are similar.) Signs of depression include: Sad or depressed mood Feelings of guilt or worthlessness Loss of interest in activities that were once enjoyable Sleep disturbances – either sleeping too much or too little Changes in appetite or eating Sexual difficulty Loss of energy Feeling constantly anxious or worried Signs of diabetes include: Increased or excessive thirst Excessive hunger Increased urination Irritability and mood disturbances Weight loss despite increased appetite Fatigue Blurred vision A fruity odor to the breath (ketoacidosis) Poor wound healing Dry mouth Impotence in men Recurrent fungal and bacterial infections

According to the American Diabetes Association, the rate of depression among diabetics is between 15 and 20 percent. In the general population, the rate is estimated to be roughly three to five percent. In addition, a Johns Hopkins study conducted in 2004 reviewed the case histories of over 11,000 people and found that depressive symptoms were a predictor for type 2 diabetes.

Now, new research from Kaiser Permanente and the Washington University School of Medicine in St. Louis has uncovered important findings about the relationship between depression and diabetes.

Kaiser Permanente researchers examined the medical histories of 1680 research participants and found that people with diabetes were more likely to have been treated for depression within the six months leading up to their diagnosis.

Patrick Lustman, PhD, led the study at Washington University. He and his research team found that depressed diabetics experienced improvements in blood sugar and decreased levels of depression after only eight weeks of treatment with fluoxetine, a widely available antidepressant marketed by the brand name Prozac.

The precise link between depression and diabetes has not yet been determined, but there are several hypotheses about how the two interact. Many medical experts believe that the stress and suffering of dealing with a chronic illness, as well as feeling isolated because of the need to pay so much attention to things that most people do not have to think about, may precipitate depressive episodes.

Others believe that those who are depressed are less likely – or, in the case of significantly compromised cognitive functioning, unable – to follow regimens that keep them healthy, which may lead to a vicious cycle of worsening complications and worsening depression. 

As for the effectiveness of the antidepressant regimen in combating high blood sugar, Dr. Lustman hypothesized that it may have something to do with fluoxetine’s ability to tone down the body’s response to the hormone cortisol, which is released in response to stress – and increases the insulin resistance that can cause diabetes.

Whatever the reasons, it is clear that there is a link between these two chronic, and potentially dangerous, conditions. Diabetics who notice the symptoms of depression should take preventive action and speak to their doctors before their symptoms worsen.  Similarly, those who have had depressive episodes should remain aware of the increased likelihood that depressives will be diabetic at some point in their lives. In addition, it is a good idea for people with loved ones who have one condition to be aware of the signs of the other.