Depression and Diabetes

Diabetes is an epidemic throughout the world. In 2014, 9% of the world’s adult population had been diagnosed with the disease,1 with 29 million living in the United States.2 Depression is also epidemic, with the global burden close to 350 million and 18 million in the United States.3,4 When these two diseases are co-morbidities, the negative effects on health are significant.

Patients with diabetes who also have depression have higher hemoglobin A1C levels, higher frequency of suicide, higher use of ambulatory care and a 4.5 times higher total healthcare expenditures compared to people without depression.5-7 In 2012, the total economic cost of diabetes in the United States was $322 billion.8

With depression expected to be the second leading cause of disability by 2020,9 vigilant and ongoing assessment of depression symptoms in patients with diabetes is of upmost importance.


Available Tools
Patients with diabetes are twice as likely to develop depression as the general population.10 Depression as a co-morbidity in patients with diabetes is often associated with infrequent blood glucose monitoring, decreased physical activity and poor adherence to a healthy diet.5 This increases the risk for diabetes complications such as retinopathy, peripheral neuropathy, kidney disease and macrovascular complications, which can result in loss of sight, need for kidney transplant or amputation.10 Primary care providers who routinely manage and spend more time with diabetes patients are uniquely positioned for early recognition of depressive symptoms.

Assessing Depression in Diabetic PatientsAlthough many studies have documented the negative impact of depression on diabetes, a large population of patients with diabetes (about 45%) have untreated or undertreated depression. 11-13 The American Diabetes Association includes routine screening for psychosocial problems such as depression as one of the 2014 Standards of Care for patients with diabetes-especially with the discovery or increased likelihood of complications.14 But current guidelines do not provide recommendations or guidance about which screening tools to utilize. The nine-question Patient Health Questionnaire (PHQ-9) is frequently used in primary care due to its known efficacy, but some questions related to somatic symptoms, such as the common diabetes-related symptoms of fatigue and sleep difficulty, may lead to a falsely elevated score in patients with diabetes.15

The World Health Organization Five-Item Well-Being Index (WHO-5) is a reliable screening tool to detect depression in patients with diabetes .16 The WHO developed this tool in 1998 to assess well-being in a European study of patients with diabetes. It is a short, positively worded five-question survey that assesses mood, vitality and general interests over the previous 2-week period. It has sensitivity and specificity in detecting likely depression similar to that of the PHQ-9, but it also monitors well-being over time, which the PHQ-9 does not.17

SEE ALSO: Mental Health Outeach

With a Flesch Reading Ease score of 70, the wording of the WHO-5 can be easily understood by anyone with an 8th grade education.18 Its use has been validated for adolescents with diabetes.19 The noninvasive, optimistic wording of the WHO-5 Index may also help alleviate some of the negative stigma associated with depression, thereby allowing for more honesty when answering the questions and providing a more accurate reflection of the patient’s true well-being.

The WHO-5 Index uses a 6- point Likert Scale to rate the questions (0 = not present and 5 = constantly present). Raw scores are calculated by adding the numbers associated with the answers together. The highest score is 25 and the lowest score is 0. Higher scores correspond with better-perceived well-being.

To calculate percentage scores, add the numbers together and multiply the sum by 4. Raw scores lower than 13, any “0” or “1” responses to any of the five questions, or a percentage score below 50% necessitates further investigation. An in-depth psychological and physiologic assessment is necessary to rule out other possible causes of symptoms before diagnosing depression. Measurement of well-being over time can also be monitored by using percentage scores. A 10% difference in scores is indicative of significant change in well-being.19


Importance of Screening
Screening for depression in patients with diabetes is as important as routinely checking A1C levels. Regular depression screening and assessment of overall well-being should be included in the management and plan of care for all patients with diabetes. Depression is a negative prognostic indicator for diabetes.20

Routine screening with the WHO-5 Index can lead to early detection of depressive symptoms, thereby allowing providers to appropriately recognize and promptly treat depression in this population. Patients who screen positive with the WHO-5 Index may benefit from a more in-depth mental health evaluation or referral, since the diagnosis of depression can often include or mimic other psychiatric comorbidities.

Although early detection and prompt treatment are important, follow-up and continued assessment and monitoring of well-being are also necessary. This highlights an additional strength of this tool. The WHO-5 Index provides an easy, quick and reliable way to detect likely depression in patients with diabetes and to monitor well-being over time. This can lead to a potential decrease in diabetes-related complications and improved health and well-being for these patients.


1. World Health Organization. Global Status Report on Noncommunicable Diseases 2014.

2. Centers for Disease Control and Prevention. National Diabetes Statistics Report: Estimates of Diabetes and its Burden in the United States, 2014.

3. World Health Organization. Depression.

4. Greden JF. Physical symptoms of depression: unmet needs. J Clin Psychiatry. 2003;64(Suppl 7):5-11.

5. Katon WJ. The comorbidity of diabetes mellitus and depression. Am J Med. 2008;121(11 Suppl 2):S8-S15.

6. Egede LE, et al. Comorbid depression is associated with increased health care use and expenditures in individuals with diabetes. Diabetes Care. 2002;25(3):464-470.

7. Sarkar S, Balhara YP. Diabetes mellitus and suicide. Indian J Endocrinol Metab. 2014;18(4):468-474.

8. Dall TM, et al. The economic burden of elevated blood glucose levels in 2012: Diagnosed and undiagnosed diabetes, gestational diabetes mellitus and prediabetes. Diabetes Care. 2014;37(12):3172-3179.

9. Reddy MS. Depression: the disorder and the burden. Indian J Psychological Med. 2010;32(12):3172-3179.

10. de Groot M, et al. Association of depression and diabetes complications: A meta-analysis. Psychosom Med. 2001;63(4):619-630.

11. Gonzalez JS, et al. Depression, self-care, and medication adherence in type 2 diabetes: Relationships across the full range of symptom severity. Diabetes Care. 2007;30(9):2222-2227.

12. Park M, et al. Depression and risk of mortality in individuals with diabetes: A meta-analysis and systematic review. Gen Hosp Psychiatry. 2013;35(3):217-225.

13. Li C, et al. Prevalence and correlates of undiagnosed depression among U.S. adults with diabetes: The Behavioral Risk Factor Surveillance System, 2006. Diabetes Res Clin Pract. 2009;83(2):268-279.

14. American Diabetes Association. Standards of medical care in diabetes-2014. Diabetes Care. 2014;37(1):14-80.

15. Reddy P, et al. Identification of depression in diabetes: The efficacy of PHQ-9 and HADS-D. Br J Gen Pract. 2010;60(575):e239-e245.

16. Topp CW, et al. The WHO-5 well-being index: A systematic review of the literature. Psychother Psychosom. 2015;84(3):167-176.

17. Hermanns N, et al. Screening, evaluation and management of depression in people with diabetes in primary care. Prim Care Diabetes. 2013;7(1):1-10.

18. De Wit M, et al. Validation of the WHO-5 well-being index in adolescents with type 1 diabetes. Diabetes Care. 2007;30(8):2003-2006.

19. About the WHO-5.

20. Voinov B, et al. Depression and chronic diseases: It is time for a synergistic mental health and primary care approach. Prim Care Companion CNS Disord. 2013;15(2):10.4088/PCC.12r01468.


Christina Sweatman is a student in the DNP program at the Medical University of South Carolina and a registered nurse at Roper St. Francis Hospital in Charleston, S.C. Joy Lauerer and Charlene Pruitt are assistant professors at the Medical University of South Carolina.

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