DIABETES, DEPRESSION AND ANXIETY

Compared to those who don’t have diabetes, people living with diabetes are at significantly higher risk of developing mental health conditions such as depression and anxiety.

• Depression is characterized by persistent sadness, loss of interest, fatigue, sleep disturbances, and sometimes suicidal thoughts.
• Anxiety is characterized by nervousness, restlessness, tension, feelings of panic, dread, or danger, rapid heartbeat and breathing, sweating, trembling, muscle twitching, difficulty concentrating, insomnia, and gastrointestinal issues like nausea or diarrhea.

Diabetes and depression

A recent systematic review and meta-analysis including ~2,500 people with type 1 and ~120,000 with type 2 diabetes, found that the prevalence of depression was approximately twice as high in people with type 1 (22%) and type 2 diabetes (19%), compared to those without diabetes (11 to 13%).
Depression can negatively affect diabetes management by impairing self-care behaviours such as glucose monitoring, diet, exercise, and medication adherence. This may lead to poorer glycemic management and higher glycated haemoglobin (HbA1c) levels.

Therefore, unsurprisingly, depression in diabetes is associated with increased risk of both microvascular (e.g., peripheral vascular disease, sexual dysfunction, etc…) and macrovascular complications (e.g., heart attack and stroke), reduced quality of life, functional disability, and higher rates of death.

Diabetes and anxiety

A systematic review and meta-analysis including ~12,500 people with diabetes found that diabetes was associated with anxiety disorders and symptoms, with a 25% increased risk overall. Indeed, more recent Australian research suggests that one in five people with insulin-treated type 2 diabetes and one in six with type 1 diabetes or non-insulin treated type 2 diabetes have moderate-to-severe anxiety symptoms.

Anxiety is associated with poorer diabetes self-management, including reduced physical activity, unhealthy behaviours (e.g., smoking, excessive alcohol consumption), and suboptimal blood glucose management (e.g., elevated HbA1c). It increases the risk of diabetes-related complications and co-morbidities and is often accompanied by depressive symptoms, further impairing quality of life.

Anxiety can contribute to “diabetes distress”, a condition characterised by emotional burdens related to managing diabetes, leading to frustration, worry, low motivation, and avoidance of care. Fear of hypoglycaemia (blood glucose < 4.0 mmol/L or 70 mg/dL) is also a common form of anxiety among people with diabetes.

Diet, depression and anxiety

As mentioned in this month’s Food for Thought, there is evidence from systematic reviews and meta-analyses of randomised controlled/clinical trials that a healthy diet can improve some symptoms of depression. Unfortunately, none of these specifically focus on people with diabetes, although they do include some studies that involved people with diabetes.

The first, conducted in 2018, included a total of 16 studies with ~46,000 participants. It found that dietary interventions significantly reduced depressive symptoms, but did not have an effect on anxiety symptoms. The dietary interventions primarily aimed to (a) reduce bodyweight, (b) improve nutrition, or (c) decrease dietary fat intake. They had some common features, such as aiming to reduce the intake of discretionary foods, while replacing these with high-fibre, nutrient dense alternatives, such as vegetables.

The most recent, conducted in 2023, included studies on dietary changes, as well as studies on physical activity and sleep hygiene, and incorporated a total of 97 studies. It found that lifestyle changes improved symptoms of depression in people overall, and also in people with or at risk of diabetes. For anxiety, lifestyle changes improved symptoms for people overall, but did not improve anxiety in people with diabetes.

Glycemic index and depression

There is also evidence from systematic reviews/meta-analyses of observational studies and randomised controlled/clinical trials that a low GI diet can improve some symptoms of depression. Once again, they did not specifically focus on people with diabetes, but they include some studies that involved people with diabetes. There were no studies that specifically looked at anxiety.

The first included a total of 6 observational studies with ~76,000 participants. It found that there was evidence that high GI diets were associated with increased risk of depression but evidence for GL (glycemic load) was mixed.

The second included a total of 6 studies with ~101,000 participants. It found that there were no associations between GI or GL in cross-sectional studies. However, in prospective cohort studies, there was a small but statistically significant (13%) association between high GI diets and risk of depression, and in clinical trials, there was a significant change in depression scores after consumption of a high-GL diet.

Conclusion

People with diabetes are at greater risk of depression and anxiety than people without the conditions. There is some evidence that a healthy diet, particularly those containing high-fibre, low GI, nutrient dense foods may help with depression, but there is currently little evidence that they help with anxiety. As is often the case, more high-quality research is needed.

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