Diabetes Mellitus

Diabetes mellitus is a serious chronic illness. More than 17 million people in the United States have diabetes and at least 16 million have prediabetes (they are highly likely to develop the disease), and the numbers are growing fast. The number of adults with diabetes in the United States is expected to increase 165 percent over the next 50 years. Diabetes is the seventh leading cause of death, and due to the complications of the disease, is a major cause of blindness, amputations, heart disease, and stroke. Diabetes has become a major focus of health psychology because it has been shown that the course and outcome of the disease are strongly affected by how patients behave and take care of themselves. In order to understand the psychology of diabetes, one must first understand the biology.

Biology of Diabetes Mellitus

The cells of our bodies use the food that we eat for growth and energy by turning part of the food into glucose (sugar), which is found in the bloodstream. The pancreas (an organ in the abdomen) produces a hormone (insulin) that signals the cells to allow the glucose to enter them and be used and stored. Diabetes is a disorder of this metabolic process. There are two major types of diabetes. Type 1 diabetes occurs when the pancreas produces little, if any, insulin. People with Type 1 diabetes must give themselves insulin regularly, usually by injection, or they will get very sick and could die. About 5-10 percent of people with diabetes have Type 1; it usually appears suddenly and mostly in children and young adults. The remaining 90-95 percent have Type 2 diabetes, which is strongly linked to obesity. Type 2 diabetes usually develops gradually in older adults. However, there are growing numbers of children who are being diagnosed with Type 2 diabetes. Type 2 diabetes occurs when the body does not produce enough insulin and/or is not able to use the insulin that is made as well as it should. (Gestational diabetes is a third type of diabetes, it occurs during pregnancy and usually resolves after the baby’s birth; however, one-third of women who have had gestational diabetes will later develop Type 2 diabetes.) In all types, the glucose does not get into the cells properly or sufficiently and builds up in the blood causing high blood sugar {hyperglycemia). People are diagnosed with diabetes when their blood sugars are very high; this usually causes symptoms of excessive thirst and hunger, frequent urination, and fatigue.

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People with diabetes need to try to maintain normal blood glucose levels. Studies have clearly shown that when patients change their behavior to control their blood sugar they can prevent or delay the serious complications that often develop from the disease (i.e., eye disease, kidney damage, heart disease, nerve damage). A landmark study in 2001 also showed that when people who are at risk for diabetes lose weight and increase their activity level, they may even prevent the onset of the disease (Delamater et al., 2001). People with diabetes should do several things to manage the disease. The diabetes self-care regimen includes (1) frequent and regular blood glucose testing, (2) meal planning and dietary control, (3) exercise, and (4) taking prescribed medications.

Psychology of Diabetes Mellitus

One can see that the diabetes care regimen is all about self-care behaviors. People with the most common form, Type 2, are often overweight and live inactive, sedentary lives. When they are diagnosed, they have to make major lifestyle changes to closely watch and control what and when they eat, begin to exercise, and properly take medications (which may include regular insulin injections). There are several psychological factors that affect how well they make these changes and the quality of life they experience with this illness. The most well-studied are the influences of depression and stress.

Depression and Diabetes

Major depression is a mental illness that is twice as common in people with diabetes as in healthy people. People are diagnosed with major depression when they experience persistent feelings of sadness or lack of interest in previously pleasurable activities (anhedonid) as well as other symptoms, such as sleep, appetite, and concentration problems. Depression persists over time, it may not get better without treatment, and even when successfully treated, is likely to occur again. Depression is associated with poor blood glucose control as well as higher cholesterol levels (which also increase the risk of heart disease).

Why do individuals with diabetes get depressed? Depression may be physiological and be due to possible changes in brain chemicals and/or hormones that are common to both diabetes and depression, or it may be a biological response to chronic high, low, or variable blood sugar levels.

Living with diabetes also poses many emotional challenges that can overwhelm one s psychological resources and lead to depression. Patients need to control a basic activity of life, namely eating, which can lead to a feeling of loss of control over one’s own body. Patients can feel ashamed of the stigma of having a chronic illness. Because diabetes is a hidden disease (one cannot tell if someone has diabetes just by looking at them), some people do not get enough emotional support from others. Also, patients often feel guilty about their less-than-perfect self-care. Finally, patients experience fear about the high likelihood that they will develop complications. They generally feel highly anxious when the first complication is diagnosed.

Serious complications of diabetes also add to the burden of the disease. Some people develop sexual dysfunction. For men, this may mean impotence; for women it may mean pain and decreased desire. Sexual dysfunction is very difficult to talk about; patients often do not even tell their doctors when it happens. Sexual dysfunction can affect how people feel about themselves, causing low self-esteem and feelings of shame. These problems and feelings can interfere with the relationship with one’s partner, who may not understand why his or her sexual life has changed.

Another major complication can be kidney disease, which in some cases requires hemodialysis. This is a process in which the patient’s blood is cleansed of impurities when the kidneys are not functioning properly and are unable to do so. It requires that the patient be hooked up to a dialysis machine three times per week, every week. One can imagine how much this would disrupt an individual’s life and routines, interfering with work, recreation, and family activities. Thus, dealing with complications can also cause and increase depression. Research shows that the more complications an individual has, the poorer quality of life he or she experiences.

Depression can make diabetes self-care worse by affecting what one does and does not do. Someone who is depressed is less likely to take good care of himself or herself. The person feels hopeless and helpless, and may not even try to stick to a diet, exercise, or self-care regimen. Also, many people will overeat when they are depressed. This can cause weight gain and poor blood glucose control. Alcohol and illegal drug abuse are also ways people try to cope with depression, and both will further impair the health and self-care regimen of the individual with diabetes.

Because depression can significantly interfere with optimal diabetes self-management and is a debilitating illness itself, it is important to diagnose and treat depression when it exists with diabetes. The two main ways to treat depression are with antidepressant medications and psychotherapy. These interventions with individuals with diabetes are only beginning to be studied. A 1997 study of antidepressants with depressed individuals with diabetes showed that, compared to patients treated with a placebo, the medication improved the depressive symptoms. It was less clear that it improved blood glucose control, but there was a trend in this direction. A 1998 study of cognitive-behavioral therapy (CBT; a form of psychotherapy that aims to help patients change their negative thoughts and behaviors) with a group of Type 2 diabetes patients also found that the depression improved. The blood sugar control of patients treated with CBT did not improve immediately, but was significantly improved compared to controls at 6 months follow-up. More research on the effect of treatment of depression on diabetes is needed.

Stress and Diabetes

When we are in situations that are new, challenging, or frightening, our bodies react by experiencing what is called the stress response. This has also been called the fight-or-flight response, as it is the body’s way of getting ready to deal with the situation by running or getting away. In earlier times, this worked well when, for example, one had to deal with a tiger in the path. However, in modern times, the situations that cause people to react with the stress response are different; one often cannot run or fight. Examples of stressful situations might be having a talk with a teacher, taking an exam, or starting a new relationship.

Several studies of Type 2 diabetes patients showed that stress can negatively affect blood sugar control; this is less clear for those with Type 1 diabetes. This may happen in several ways. From a physical perspective, it is known that when a person experiences the stress response their body releases several hormones (e.g., epinephrine, Cortisol) to mobilize the body’s systems. This can result in higher blood glucose levels, which is normal, but a problem if one has diabetes and his or her blood glucose regulation system is already out of balance. From a behavioral perspective, it is known that when people experience stress it affects what they do and how well they take care of themselves. Stress may cause a diabetes patient to skip meals or overeat, pay less attention to the need for regular blood glucose testing, forget to take medications or attend doctor visits, and abuse alcohol or other drugs. These changes in self-care can also affect blood glucose levels and are thus considered indirect effects of stress on diabetes.

Stress management training is an intervention that aims to teach patients skills to help them cope with their high stress levels effectively. People cannot avoid stress but can learn to deal with it so that it does not negatively affect health. Examples of the skills taught in stress management training include progressive muscle relaxation (systematically relaxing all the muscles of the body), mental imagery (imagining a relaxing scene, like being at the beach), diaphragmatic breathing (taking deep, relaxing breaths), and cognitive restructuring (changing negative, anxiety-producing thoughts to positive, anxiety-decreasing thoughts). Several studies in which diabetes patients have been taught these skills demonstrated that learning to manage stress can improve blood sugar control. However, other studies did not support this conclusion, and more research needs to be done in this area.

Regimen Adherence and Strategies for Behavior Change

The self-management regimen that individuals with diabetes must adhere to requires significant behavior change. They must exercise and maintain strict dietary control, both to establish and maintain a healthy weight and to achieve normal blood glucose levels. They must test their blood glucose frequently and regularly, which involves multiple uncomfortable pinpricks, to monitor their levels and adjust meals, medications, and/or activity level accordingly. They must often take multiple medications; if it is insulin, this is usually by self- injection. They also need to check their feet daily for possible injuries and healing problems. How well an individual does all of this is called adherence to the diabetes self-care regimen.

There are many reasons that regimen adherence is very difficult. Some people do not have enough information about diabetes; one needs sound information to know what to do. They may not even know how important it is to take good care of themselves and that doing so will help them avoid complications. Some people have unrealistic goals, they try to change but get frustrated when the results are not fast enough. Some do not have the support of others; it is especially hard to change when no one is helping. Others do not have enough resources in their lives. For example, they do not have medical insurance to pay for their doctor visits or blood testing supplies. For others, life is already very stressful and adding the skills needed to deal with diabetes feels overwhelming, so they just avoid doing what they should.

Several psychological factors have been shown to relate to poor adherence. Patients with limited cognitive abilities and poor motivation often demonstrate poor adherence. Also, some patients have beliefs about diabetes that interfere with adherence. For example, patients who believe that the regimen that was prescribed for them by their doctor is unsuitable are less likely to follow that regimen. Those who minimize the seriousness of the disease are also less likely to adhere. A positive predictor of adherence is self-efficacy, or the confidence in one’s ability to carry out the regimen tasks. A person who thinks he or she can do it is more likely to. The importance of social support has also been demonstrated, with those who feel emotionally supported by family and/or friends being more likely to adhere to the prescribed regimen.

Two areas of the self-care regimen that have been studied are adherence to blood glucose testing and adherence to diet and weight loss.

Weight loss and management are the most difficult aspects of the diabetes regimen. There are strategies for behavior change that have been demonstrated to improve adherence to weight loss. Interventions to teach these strategies have shown some success. First, patients are encouraged to set clear and reasonable goals. For weight management, this means aiming for a 2-lb, not a 10-lb, loss per week. Second, patients are encouraged to focus on changing their behaviors, not their numbers. This might mean switching to a low-fat diet rather than focusing on how many pounds they have lost. Third, they are urged to start with small, achievable steps and focus on one behavior at a time. This includes making small changes that help them make peace with food (e.g., trying to increase one’s awareness of hunger and attention to taste). Fourth, patients are educated about the importance of social support and helped to take steps to identify a confidante and ask for help.

Weight loss programs that teach these principles can help overweight individuals lose weight; the average loss is about 10 percent of initial body weight. Even this modest weight loss can improve a patient’s blood glucose control and also can improve blood pressure, lipid levels (fats in the blood), and quality of life. However, after 1 year most participants in these programs regain 30 percent of their weight, and after 5 years most have regained what they lost. Participants who increase their physical activity through exercise and those who consistently monitor their weight are the most likely to keep the weight off. It is clear that we need a better understanding of how to help people maintain the losses they achieve and establish stable weight management.

Regular and frequent blood glucose testing is also an important part of the self-care regimen and is difficult to maintain, as it involves taking time to perform uncomfortable pinpricks multiple times during the day. This allows patients to watch out for extreme high or low readings (hyper- and hypoglycemia), which can signal conditions that can make them very ill, and to adjust their medications, meals, and/or activity levels. Blood glucose fluctuations affect mood, making patients nervous, frustrated, and unhappy, and often interfere with life and may be embarrassing. As time passes with the disease, patients may become less sensitive to the physical signs that their blood sugar is too high or low, so regular and frequent testing becomes even more important. Daniel Cox and his colleagues (1995) have developed a program, called Blood Glucose Awareness Training (BGAT), to help. BGAT includes education and practice of skills to help patients identify the events that affect their blood sugar and to increase their sensitivity to bodily cues of low or high sugar so that they can quickly take appropriate steps.

Diabetes Mellitus and the Bigger Picture

Whereas much of the research has emphasized the psychological and social influences of the individual and family on diabetes self-management, there is also growing recognition that the larger context of one’s life has a significant influence on self-care. This includes increased attention to the psychosocial influences of the patient’s neighborhood and worksite and the overall health care system.

Most working-age adults spend the majority of their time at work. Factors in the working environment can either promote or interfere with good diabetes management. For example, when vending machines are stocked to offer water and sugar-free drinks, it helps diabetes patients limit their intake of sugar and maintain their dietary regimen. Similarly, many companies now have gyms available to employees so that they can incorporate exercise into their busy lives more easily. When individuals with diabetes work in a setting in which their schedules are rigid and inflexible, they have more difficulty managing their illness, as they cannot take the time to test themselves. Worksites and community settings are often places where programs can be offered to screen individuals for diabetes and provide health promotion programs. These activities are especially important for populations that are medically underserved, such as minorities and the poor.

Diabetes is a demanding and challenging disease. It requires that patients make many changes in how they live their lives. It affects their relationships with others and changes how the individual sees him/himself or herself. There is no vacation from diabetes; it is with the individual all day, every day, and frequently leads to more difficult and threatening problems in the future. However, most individuals with diabetes lead long and fulfilling lives. They learn to adapt, to cope with the ups and downs of the illness, and to turn to others for education and support when problems arise. An understanding of the illness, an appreciation of the pitfalls, and a knowledge base of positive ways to cope help the individual successfully manage the burdens of diabetes. Future efforts must lead to ways that larger communities and society can support those who have diabetes to ensure successful adaptation and better quality of life.


  1. Anderson, B. J., and Rubin, R. R. (Eds.). (2002). American Diabetes Association. www.niddk.nih.gov Practical psychology for diabetes clinicians (2nd ed.) Alexandria, VA: American Diabetes Association.
  2. Cox, D. J., Gonder-Frederick, L., Polonsky, W, Schlundt, D., Julian, D., & Clarke, W. (1995). A multicenter evaluation of Blood Glucose Awareness Training-II. Diabetes Care, 18, 523-528.
  3. Delamater, A. M., Jacobson, A. M., Anderson, B., Cox, D., Fisher, L., Lustman, R, et al. (2001). Psychosocial therapies in diabetes: Report of the Psychosocial Therapies Working Group. Diabetes Care, 24, 1286-1292.
  4. Glasgow, R. E., Fisher, E. B., Anderson, B. J., LaGreca, A., Marrero, D., Johnson, S. B., et al. (1999). Behavioral science in diabetes: Contributions and opportunities. Diabetes Care, 22, 832-843.
  5. National Institute of Diabetes and Digestive and Kidney Diseases (National Diabetes Information Clearinghouse), www.niddk.nih.gov

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