Diabetes & Metabolic Syndrome: Clinical Research & Reviews
ReviewDepression in type 2 diabetes mellitus—A brief review
Introduction
Diabetes mellitus is a group of metabolic diseases that leads to a substantial reduction in life expectancy, decreased quality of life, and increased costs of care. The global prevalence of type 2 diabetes mellitus (T2DM) has been estimated to be 6.4% [1]. The World Health Organization has projected that around 300 million people will suffer from diabetes by 2025 [2]. T2DM is much more prevalent as compared to type 1 diabetes. It comprises 90% of people with diabetes around the world [3], and is caused by a combination of resistance to insulin action and an inadequate compensatory insulin secretory response [4].
Depression is a common co-morbid condition in T2DM and it has been estimated that people with T2DM are twice as likely as the general population to suffer from depression [5], [6].
Individuals with diabetes and co-morbid depression have been shown to have poor adherence to diabetes medications [7], poor adherence to dietary recommendations [7], poor glycemic control [8], more diabetes-related complications [9], and a higher risk of mortality than individuals with diabetes who are not depressed [10], [11]. American Diabetes Association (ADA) has also recommended the assessment of psychological problems like depression in the patients with diabetes [12].
Section snippets
Depression and type 2 diabetes
A relation between depression and T2DM has been indicated in several clinical reports [5], [13], [14]. However the direction of the relationship is unclear. For example the research by Knol et al. suggests that depression being a consequence of diabetes may also be a risk factor for the onset of diabetes [15]. Individuals with depression, but no diabetes, are at a higher risk for developing diabetes at follow-up. Mezuk et al. reported data showing that depression may be an important risk factor
Pathophysiology of depression and type 2 diabetes-linked
The reason for this timely relationship between depression and diabetes manifestation is unclear. It could be that people with elevated depressive symptoms are less attentive toward a healthy lifestyle, therefore increasing their risk for type 2 diabetes. Alternative explanations for this finding refer to chronic dysregulations of the hypothalamic–pituitary–adrenal (HPA) axis such as high cortisol levels and reduced insulin sensitivity or an activation of the immune system leading to or
Depression and diabetic complications
Poorly controlled diabetes leads to a number of co-morbid complications. These include diabetic retinopathy, nephropathy, neuropathy, cardiac heart diseases and peripheral vascular disease. Association between depression and various long-term diabetic complications have been reported in several studies [43], [45], [46]. The prevalence of depression in T2DM patients appears to increase with the number of diabetic complications [47]. Two recent reviews have reported that depressed mood is
Depression and glycemic control
HbA1c (glycated hemoglobin) is accepted as the best measure of recent glycemic control and is used to guide clinical management and according to the American Diabetes Association (ADA) guidelines, patients with diabetes should maintain low levels of HbA1c [12]. An explanation for the relationship of depression and T2DM stems from the study results indicating that blood glucose is itself a potent regulator for mood states. In particular, hypoglycemia or severe hyperglycemia is able to induce
Depression in non-diabetics
Lifetime prevalence of depression in the general population is 10–25% for women and from 5% to 12% for men. In any year, 5–9% of women will have this disorder and from 2% to 3% of men will have it [54], [55]. Individuals with depression experience reduced functioning and decreased quality of life [56], [57], as well as higher health care utilization and costs, and disability [58]. Furthermore, depression is more prevalent in patients with chronic illness in general [59] and diabetes in
Conclusion
Depression is a commonly associated condition with T2DM. Above studies suggest that depression is almost twice more common in patients with type 2 diabetes as compared to the general population. It can be concluded from this review that there is a need for the assessment of depression among the patients with T2DM, which is also recommended by the ADA guidelines [12]. Large epidemiological studies worldwide would help to find out the incidence of depression in T2DM at large. Further, it would
Conflict of interest statement
There was no conflict of interest involved in this study.
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Cited by (49)
The prevalence of comorbid depression in patients with diabetes: A meta-analysis of observational studies
2019, Diabetes and Metabolic Syndrome: Clinical Research and ReviewsCitation Excerpt :Depression is also associated with increased levels of glucocorticoids, catecholamines and growth hormone, which can lead to insulin resistance and diabetes development [56]. In addition, metabolic abnormalities caused by drugs used to treat depression, unhealthy lifestyle and physical inactivity increase the likelihood of developing diabetes in depressed patients [57,58]. The prevalence of depression in women was higher than that of men, which is consistent with studies conducted in China [53], Germany [59].
Assessment of comorbid mild cognitive impairment and depression in patients with type 2 diabetes mellitus
2019, Diabetes and Metabolic Syndrome: Clinical Research and ReviewsCitation Excerpt :In particular, hypoglycemia or severe hyperglycemia is able to induce negative emotional states in patients with diabetes [24]. The presence of depression in a patient with diabetes has been suggested as one of the possible causes of an inadequate metabolic control, especially for those patients who cannot achieve an adequate glycemic control despite intensive medical recommendations [25]. The present piece of work aimed to study the prevalence of comorbid Mild cognitive impairment (MCI) and depression in patients with Type 2 diabetes mellitus and its relation to glycemic control.
Association of hippocampal subfield volumes with prevalence, course and incidence of depressive symptoms: The Maastricht Study
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