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How can diabetes affect the brain and psyche?

Scientific support: Prof. Dr. Karsten Müssig

The long-term effects of inadequate diabetes mellitus management are varied and can affect numerous organs and regions of the body.

This includes the brain and psyche: Diabetes can be associated with stress, depression, and memory or eating disorders.

Increased stress associated with diabetes

Having diabetes often means stress, because it places daily demands on those affected. People with diabetes must always adhere to rules, such as regular blood sugar testing, paying to attention to their diet and trying to get enough physical activity. Many of those affected suffer because the disease determines their daily life. This is coupled with a fear of developing complications. These perpetual demands can become a permanent emotional burden and place the patient in a state of constant stress. This is known by specialists as diabetes distress.

When subjected to constant stress, the body produces increased levels of the hormone cortisol. Cortisol also increases the blood sugar level to help provide the body with more energy quickly and when needed. Additionally, being under high levels of stress increases the release of the appetite hormone ghrelin. This appetite hormone increases the desire for sweet and carbohydrate-rich foods, making the blood sugar levels likely to rise even further due to the increased food intake.

A number of investigations have shown that diabetes distress often leads to the patient taking less care of themselves. Sooner or later, this affects the success of the treatment. The diabetes is neglected, metabolic control deteriorates, and the risk of long-term complication increases.

The good news: There are many learnable methods and measures to help reduce distress. One example is regular physical activity. It is crucial to seek and accept help. For example, strategies for coping with stress can be helpful.

Concerns, worries, and fears related to diabetes can be emotionally overwhelming. A number of studies have confirmed that people with diabetes more often report anxiety and are twice as likely to show signs of depression as people of the same age with a healthy metabolism. It is estimated that 10 percent of people with diabetes are afflicted with “true” depression and approx. 25 percent suffer from depressed moods. Overall, women with diabetes more frequently suffer from depression than men.

Patients often become less motivated to implement their diabetes treatment when suffering from depressed moods or depression. Neglected treatment results in increased blood sugar levels. This is compounded by the fact that the stress hormones associated with psychological stress negatively influence the blood sugar levels. Long-term elevated blood sugar levels increase the risk of suffering from the complications of diabetes affecting the blood vessels, heart, eyes, and kidneys. Consistent treatment of depression can help improve the metabolic state associated with diabetes.

Good to know:

The Working Group Diabetes and Psychology e.V. of the German Diabetes Association provides information, addresses, and a self-test (WHO 5 wellbeing test) online: (Link in German)

Not every dejected emotional state is automatically depression or depressed mood. Temporarily feeling dejected or sad is a normal part of life.

However, when the feeling of dejection persists over a longer period of time, i.e., several weeks or months, depression or depressed mood may be the underlying cause. Depression is often underestimated and kept secret by those affected.

Questionnaires can help patients and their treating physicians to identify an existing case of depression. This is important because people affected by depression require therapeutic help. When depression is diagnosed, if necessary, the doctor can refer the patient to a psychologist or psychotherapist. The drug-based treatment of depressive disorders is also possible.

Specialists refer to depressed mood when symptoms such as dejection, increased need for sleep, constant fatigue, and lack of motivation are evident for a limited time period. The symptoms of depressed mood are also milder than those of depression. Depressed mood is also defined as a pathological change to the frame of mind. However, compared to depression, it passes without therapeutic help. Nevertheless, it can be beneficial for those affected to seek help in coping with their low mood.

Good to know:

Typical signs of depression include, for example, persistent

  • Sadness
  • Lack of motivation, inner restlessness
  • Difficulty thinking and concentrating
  • Feelings of guilt and inferiority
  • Loss of interest, listlessness
  • Feelings of anxiety
  • Sleep disorders
  • Loss of appetite
  • Deep despair, suicidal thoughts

Scientists have discovered that depression and type 2 diabetes may have a common biological cause. The findings focus on chronic low-grade inflammation and defective regulation of the hypothalamic-pituitary-adrenal axis. This axis controls the ability of the body to appropriately react to stress. Defective regulation can result in insulin resistance, cardiovascular disease, depression, and the onset or worsening of type 2 diabetes. The biological underpinnings of depression associated with type 1 diabetes have been subject to less study.

Memory performance and dementia

There are many potential causes of increasing forgetfulness or difficulty concentrating. There is not always a serious underlying condition in these cases. Everyone has experienced suddenly not being able to recall a name or simply forgetting an appointment. However, when episodes of impaired memory become more frequent, this can indicate the early signs of dementia. Dementia affects the ability to retain and recall information and is especially noticeable with regard to short-term memory. Patients with advanced dementia are often unable to recall the current year, month, or day. In some cases, they even forget their own name or birthday. Changes in personality, states of confusion, or orientation problems are also common. It can become so severe that those affected are unable to find their way around their own living space.

People with diabetes more frequently have impaired cognitive function and are at greater risk of developing dementia than people with a healthy metabolism. People with diabetes are twice as likely to develop dementia during their lifetime as a person of the same age without diabetes. The good news: There are many ways to reduce the risk of developing dementia – including and especially for people with diabetes.

Specialists assume that there are several causes of the elevated risk of dementia associated with diabetes. These include poor management of blood sugar, blood pressure, and blood lipids, smoking, lack of physical activity, obesity and depression. Based on current knowledge, lack of physical activity is one of the primary drivers of dementia in later life. This also applies to people without diabetes.

Alongside elevated blood sugar levels, severely low blood sugar levels can also promote the onset of dementia. Study data shows that 3 or more cases of severely low blood sugar levels double the risk of later suffering dementia.

People with type 2 diabetes and those with vascular complications are most commonly affected by dementia. These patients can develop vascular dementia during their lifetime. Vascular dementia is dementia that develops as a result of circulatory problems in the brain.

Studies focusing on people with type 2 diabetes have shown a clear correlation between vascular dementia and the long-term quality of blood sugar, blood pressure, and blood lipid management. The better these components of metabolic syndrome are regulated, the lower risk of later developing dementia.

Good to know:

The blood vessels in the brain supply the nerves cells with oxygen and nutrients. If the vessels are damaged, the nerve cells can no longer sufficiently regenerate themselves. When the damaged nerve cells are no longer being replaced, the level of damage over the years builds up, eventually resulting in dementia.

Alzheimer's disease is a subtype of dementia. In the brains of people with Alzheimer's disease, typical protein deposits (beta-amyloid plaques) and a maldistribution of tau proteins in the nerve cells can be observed. Both of these observations are deemed to correlate to damage to the brain cells.

Alzheimer's disease causes a slow and progressive deterioration of nerve cells and neuronal connections. As increasing numbers of nerve cell begin to die off, mental faculties are lost. This eventually results in memory loss. The character of those affected can also change, as not only thinking capacity but also their emotional and social skills become ever more impaired.

It has been known for many years that the risk of developing Alzheimer's disease is almost twice as high for people with diabetes compared to people with a healthy metabolism.

Scientists have discovered the first interrelationships between Alzheimer's disease and diabetes mellitus. Those suffering from Alzheimer's disease appear to show changes to their glucose metabolism early on. Among other things, it has been shown that the nerve cells of people with Alzheimer's disease are insulin resistant. Insulin resistant cells are less able to break down beta-amyloid, which may result in an increased build-up of beta-amyloid plaques.

Insulin resistance is when there is a reduced response of cells to the hormone insulin, and it plays a significant role in type 2 diabetes. This causes the muscles, liver, and fatty tissue all to display less sensitivity to insulin, which in turn increases the blood sugar levels and promotes disruption to the fat metabolism processes.

Further similarities are the chronic low-grade inflammatory processes found in the body or brain associated with both diabetes and Alzheimer's disease.

Eating disorders associated with diabetes

Diabetes is associated with a higher risk of eating disorders. Binge eating disorder plays a role particularly in type 2 diabetes. Patients omitting to take their oral antidiabetics is also often reported.

In the case of type 1 diabetes, the intentional skipping of insulin administration to promote weight loss, known as diabulimia, is the primary focus. A further type of eating disorders, one that involves binge eating followed by vomiting or the use of laxatives (bulimia nervosa), has also been observed in adolescent girls with type 1 diabetes.

Risk factors for the onset of eating disorders in patients with diabetes include a younger age, being female, heavier body weight, dissatisfaction with body image, and depression. Many of those affected tend to deny or trivialize their eating disorder.

Eating disorders must be seen as a disease. The consequence of an eating disorder in people for diabetes is poor blood sugar regulation, resulting in a higher risk of complications, such as nephropathy, retinopathy, or cardiovascular diseases. Therefore: The earlier professional help is sought to treat an eating disorder, the better.

Recurring “attacks” of excessive eating are typical for binge eating disorder. It usually affects people with type 2 diabetes who have lost control over their eating behavior, causing them to eat excessive amounts in a short period of time.

Diabulimia is most commonly seen in girls and young women with type 1 diabetes. Because insulin promotes weight gain, the required insulin doses are skipped. The discontinuation of insulin to achieve weight loss is dangerous. As the diabetes is basically being left untreated, this poses a serious risk of potentially life-threatening complications, such as diabetic ketoacidosis, which results in a severe build-up of acid in the body.


Bali, A. et al.: An Integrative Review on Role and Mechanisms of Ghrelin in Stress, Anxiety and Depression. In: Curr Drug Targets, 2016, 17: 495-507
Bundeszentrale für gesundheitliche Aufklärung: Essstörungen. (Letzter Abruf: 11.11.2019)
Chatterjee, S. et al.: Type 2 diabetes as a risk factor for dementia in women compared with men: a pooled analysis of 2.3 million people comprising more than 100,000 cases of dementia. In: Diabetes Care, 2016, 39: 300-307
Cheng, G. et al.: Diabetes as a risk factor for dementia and mild cognitive impairment: a meta-analysis of longitudinal studies. In: Intern Med J, 2012, 42: 484-491
Chireh, B. et al.: Diabetes increases the risk of depression: A systematic review, meta-analysis and estimates of population attributable fractions based on prospective studies. In: Prev Med Rep, 2019, 14: 100822
Croteau, E. et al.: A cross-sectional comparison of brain glucose and ketone metabolism in cognitively healthy older adults, mild cognitive impairment and early Alzheimer‘s disease. In: Exp Gerontol, 2018, 107: 18-26
Deutsche Alzheimer Gesellschaft e. V.: (Letzter Abruf: 08.11.2019)
Diabetes und Psychologie e. V.: (Letzter Abruf: 29.10.2019)
Fan, Y. C. et al.: Increased dementia risk predominantly in diabetes mellitus rather than in hypertension or hyperlipidemia: a population-based cohort study. In: Alzheimers Res Ther, 2017, 9: 7
Herder, C. et al.: Associations between inflammation-related biomarkers and depressive symptoms in individuals with recently diagnosed type 1 and type 2 diabetes. In: Brain Behav Immun, 2017, 61: 137-145
Joseph, J. J. et al.: Cortisol dysregulation: the bidirectional link between stress, depression, and type 2 diabetes mellitus. In: Ann N Y Acad Sci, 2017, 1391: 20-34
Kreider, K. E.: Diabetes Distress or Major Depressive Disorder? A Practical Approach to Diagnosing and Treating Psychological Comorbidities of Diabetes. In: Diabetes Ther, 2017, 8: 1-7
Lloyd, C. E. et al.: Prevalence and correlates of depressive disorders in people with Type 2 diabetes: results from the International Prevalence and Treatment of Diabetes and Depression (INTERPRET-DD) study, a collaborative study carried out in 14 countries. In: Diabet Med, 2018, 35: 760-769
Luck, T. et al.: Prävention von Alzheimer-Demenz in Deutschland. In: Nervenarzt, 2016, 87: 1194-1200
Moulton, C. D. et al.: The link between depression and diabetes: the search for shared mechanisms. In: Lancet Diabetes Endocrinol, 2015, 3: 461-471
Narita, Z. et al.: Physical activity for diabetes-related depression: A systematic review and meta-analysis. In: J Psychiatr Res, 2019, 113: 100-107
Norton, S. et al.: Potential for primary prevention of Alzheimer‘s disease: an analysis of population-based data. In: Lancet Neurol, 2014, 13: 788-794
Nouwen, A. et al.: Longitudinal associations between depression and diabetes complications: a systematic review and meta-analysis. In: Diabet Med, 2019, 36: 1562-1572
Ott, A. et al.: Diabetes mellitus and the risk of dementia: The Rotterdam Study. In: Neurology, 1999, 53: 1937-1942
Petrak, F. et al.: Depression and Diabetes. In: Endotext [Internet]., Inc. 2018
Pinhas-Hamiel, O. et al.: Eating disorders in adolescents with type 1 diabetes: Challenges in diagnosis and treatment.  In: World J Diabetes, 2015, 6: 517-526
Pinhas-Hamiel, O. et al.: Eating disorders in adolescents with type 2 and type 1 diabetes. In: Curr Diab Rep, 2013, 13: 289-297
Snoek, F. J. et al.: Constructs of depression and distress in diabetes: time for an appraisal. In: Lancet Diabetes Endocrinol, 2015, 3: 450-460
Staite, E. et al.: 'Diabulima' through the lens of social media: a qualitative review and analysis of online blogs by people with Type 1 diabetes mellitus
and eating disorders
. In: Diabet Med, 2018, 35: 1329-1336
Tomlin, A. et al.: The influence of cognition on self-management of type 2 diabetes in older people. In: Psychol Res Behav Manag, 2016, 9: 7-20
Toni, G. et al.: Eating Disorders and Disordered Eating Symptoms in Adolescents with Type 1 Diabetes. In: Nutrients, 2017, 9: 906
Tortelli, R. et al.: Midlife metabolic profile and the risk of late-life cognitive decline. In: J Alzheimers Dis, 2017, 59: 121-130
van Gemert, T. et al.: Cognitive Function Is Impaired in Patients with Recently Diagnosed Type 2 Diabetes, but Not Type 1 Diabetes. In: J Diabetes Res,  2018, 2018: 1470476
Wagner, J. A. et al.: A Randomized, Controlled Trial of a Stress Management Intervention for Latinos with Type 2 Diabetes Delivered by Community Health Workers: Outcomes for Psychological Wellbeing, Glycemic Control, and Cortisol. In: Diabetes Res Clin Pract, 2016, 120: 162-170
Whitmer, R. A. et al.: Hypoglycemic episodes and risk of dementia in older patients with type 2 diabetes mellitus. In: JAMA, 2009, 301: 1565-1572
Yaffe, K. et al.: Association between hypoglycemia and dementia in a biracial cohort of older adults with diabetes mellitus. In: JAMA Intern Med, 2013, 173: 1300-1306
Young, V. et al.: Eating problems in adolescents with Type 1 diabetes: a systematic review with meta-analysis. In: Diabet Med, 2013, 30: 189-198
Zeyfang, R. A.: Diabetes und Kognition: Prädisposition zur Demenz. In: Dtsch Arztebl, 2017, 114: 20
As of: 04.12.2019