Diabetes mellitus currently affects more than 25.8 million people of the United States’ (US) population and was the seventh leading cause of death based on US death certificates in 20071. The number of people with diabetes is predicted to increase to 29 million by 20502.The estimated total cost of diabetes in the US in 2007, including direct and indirect costs, was $174 billion1and is predicted to increase to $192 billion by 20203. Diabetes is also a leading cause of blindness, nervous system disorders, kidney disease, amputations, periodontal disease, heart disease, and stroke1.
Depression is also prevalent in the US and affects approximately 18 million people at any given time4. Recent studies have reported that the 12 month prevalence of mood disorders in the U.S. is 9.6%5, while the lifetime prevalence of a major depressive disorder in the United States is 16.2%6. Studies show that depression is a major cause of morbidity, mortality and disability7 and is associated with workplace absenteeism, diminished or lost work productivity and increased use of healthcare resources8. Finally, major depression is the second leading cause of disability-adjusted life years (DALYs) lost in women and the tenth leading cause of DALYs in men7.
Depression is prevalent in individuals with diabetes. In a meta-analysis of 42 published studies that included 21,351 adults with diabetes, the prevalence of major depression in people with diabetes was 11% and the prevalence of clinically relevant depression was 31%9. Multiple studies have established that coexisting depression in individuals with diabetes is associated with poor clinical outcomes10. Coexisting depression in people with diabetes is associated with decreased adherence to treatment, poor metabolic control, higher complication rates, decreased quality of life, increased healthcare use and cost, increased disability and lost productivity, and increased risk of death10.
Decades of research have established that treating depression in people with diabetes generally improves depressive symptoms10. Cognitive behavioral therapy appears to be the most effective psychosocial intervention, while selective serotonin reuptake inhibitors (SSRIs) appear to be the most effective pharmacologic agents11. In addition, collaborative care between primary care providers and psychiatrists appear to be effective and are associated with improved depressive symptoms11. The findings of a recent study also suggest that incorporation of spirituality into treatment may be a viable option in addition to psychosocial and pharmacological treatment for depression in people with diabetes12. While the body of evidence support treating depression in people with diabetes, there is good evidence that treatment of depression alone may not be sufficient to achieve glycemic control10. Hence, treatment should be directed at both conditions when they coexist, and combinations of CBT or pharmacologic agents (SSRIs) with oral hypoglycemic agents and/or insulin are reasonable options in these patients.
An emerging area of research is the contribution of emotional distress as an independent contributor to poor health outcomes in adults with diabetes13-17. Serious psychological distress (SPD) captures overall emotional distress that is not tied to a specific mental health diagnosis, whereas diabetes distress attempts to capture emotional distress that arises from living with diabetes13-17. There is strong evidence that both SPD and diabetes distress lead to poor diabetes outcomes13, 15, 16, 17and recent studies suggest that diabetes distress in particular, is associated with poor diabetes outcomes independent of depression13, 14, 15, 17. In light of the emerging evidence of the contribution of emotional distress to poor diabetes outcomes, it is important to understand how general distress (i.e. serious psychological distress) differs from diabetes specific distress (diabetes distress, emotional distress due to diabetes) and how they impact diabetes outcomes independent of depression. Future studies are needed to elucidate these processes in order to improve our understanding of the role of psychological factors on diabetes outcomes. In the interim, clinicians treating patients with diabetes (endocrinologists, primary care providers, nurse practitioners, physicians’ assistants and diabetes educators) need to be conversant with this emerging body of literature and learn how to incorporate the emerging evidence into their clinical practice.
In summary, this article reviews the literature on depression in diabetes, reviews the emerging literature on the role of emotional distress in diabetes, and summarizes the findings of seven recent pertinent studies in this area of research for clinicians who provide routine care for adults with diabetes. In addition, a summary of the clinical relevance of each article is provided. This should provide a good evidence base for clinicians to better understand the state of the science in the role of emotional distress in the clinical care of diabetes and its association with health outcomes.
Further Reading on Depression, Distress, and Diabetes
- Centers for Disease Control and Prevention. National diabetes fact sheet: national estimates and general information on diabetes and prediabetes in the United States, 2011. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (2011).
- Boyle J, Honeycutt A, Narayan V, Hoerger J, Geiss S, Chen H, et al. Projection of diabetes burden through 2050: impact of changing demography and disease prevalence in the U.S. Diabetes Care. 2011;24:1936-1940.
- Hogan P, Dall T, Nikolov P. Economic costs of diabetes in the US in 2002. Diabetes Care. 2003;26:917-932.
- Greden JF. Physical symptoms of depression: unmet needs. J Clin Psychiatry. 2003;64(Suppl 7): 5-11.
- Demyttenaere, K., R. Bruffaerts, J. Posada-Villa, et al. Prevalence, severity, and unmet need for treatment of mental disorders in the World Health Organization World Mental Health Surveys. JAMA. 2004. 291(21): 2581-90.
- Kessler, R.C., P. Berglund, O. Demler, et al. The epidemiology of major depressive disorder: results from the National Comorbidity Survey Replication (NCS-R). JAMA. 2003;289(23):3095-105.
- Michaud CM, Murray CJ, and Bloom BR. Burden of disease--implications for future research. JAMA. 2001;285(5): 535-9.
- US Department of Health and Human Services, Mental health: A report of the surgeon general. Rockville, MD: US Department of Health and Human Services, Substance Abuse and Mental Health Services, Substance Abuse and Mental Health Services Administration, Center for Mental Health Services, National Institutes of Health, National Institute of Mental Health, 1999.
- Anderson RJ, Freedland KE, Clouse RE, Lustman PJ. The prevalence of comorbid depression in adults with diabetes: a meta-analysis. Diabetes Care. 2001; 24(6):1069-1078.
- Egede LE, Ellis C. Diabetes and depression: global perspectives. Diabetes Res Clin Pract. 2010;87(3):302-312.
- Markowitz SM, Gonzalez JS, Wilkinson JL, Safren SA. A review of treating depression in diabetes: emerging findings. Psychosomatics. 2011; 52(1):1-18.
- Lynch CP, Hernandez-Tejada MA, Strom JL, Egede LE. Association between spirituality and depression in adults with type 2 diabetes. Diabetes Educ. 2012; 38(3):427-435.
- Fisher L, Mullan JT, Arean P, Glasgow RE, Hessler D, Masharani U. Diabetes distress but not clinical depression or depressive symptoms is associated with glycemic control in both cross-sectional and longitudinal analyses. Diabetes Care. 2010; 33(1):23-28.
- Gonzalez JS, Fisher L, Polonsky WH. Depression in diabetes: have we been missing something important? Diabetes Care. 2011; 34(1):236-239.
- Fisher L, Hessler DM, Polonsky WH, Mullan J. When is diabetes distress clinically meaningful?: establishing cut points for the Diabetes Distress Scale. Diabetes Care. 2012; 35(2):259-264.
- Egede LE, Dismuke CE. Serious psychological distress and diabetes: a review of the literature. Curr Psychiatry Rep. 2012; 14(1):15-22.
- Walker RJ, Smalls BL, Hernandez-Tejada MA, Campbell JA, Davis KS, Egede LE. Effect of diabetes fatalism on medication adherence and self-care behaviors in adults with diabetes. Gen Hosp Psychiatry. Aug 13, 2012.
- Koenig H. Spirituality and Depression: A Look at the Evidence. Southern Medical Journal 2007;100(7):737-739.
- Kessler RC, Andrews G, Colpe LJ, Hiripi E, Mroczek DK, Normand SL, et al. Short screening scales to monitor population prevalences and trends in non-specific psychological distress. Psychol Med. 2002; 32(6):959-976.