Yes, diabetes can absolutely cause mental confusion, primarily from blood sugar levels that are too high (hyperglycemia) or too low (hypoglycemia), leading to "brain fog," difficulty concentrating, and disorientation, and can also contribute to longer-term cognitive issues like dementia, notes Centers for Disease Control and Prevention (CDC), Healthline, and Mayo Clinic. Both immediate fluctuations and chronic poor control can affect brain function, causing symptoms like memory loss, difficulty solving problems, and feeling spaced out, according to Know Diabetes and Healthline.
People who have had diabetes for some time might also notice headaches due to changes in blood sugar levels. A headache can signify hyperglycemia when blood sugar levels are too high. They can also occur with hypoglycemia when blood sugar levels are too low.
Changes in blood sugar can cause rapid changes in mood and other mental symptoms such as fatigue, trouble thinking clearly, and anxiety. Having diabetes can cause a condition called diabetes distress which shares some traits of stress, depression and anxiety.
Symptoms
Diabetes often starts with mild symptoms such as feeling very hungry and tired, needing to pee a lot, being very thirsty, having a dry mouth, itchy skin, and blurry vision. Type 1 diabetes symptoms appear quickly and are more severe, while type 2 symptoms develop slowly.
Three common signs of diabetes are increased thirst and frequent urination, extreme tiredness, and blurry vision or slow-healing sores, often stemming from high blood sugar levels affecting the body. These symptoms, sometimes called the "Three Ps" (polyuria, polydipsia, polyphagia), can develop slowly in Type 2 diabetes or quickly in Type 1.
Sedentary lifestyle
Being sedentary is associated with an increased risk of type 2 diabetes. It is important to remember that even if you do the recommended amount of exercise per week you can still have a sedentary lifestyle.
Common symptoms of diabetes:
To manage diabetes, avoid sugary drinks, refined carbs (white bread, pasta, rice), processed foods, sweets (candy, cakes), unhealthy fats (fried foods, trans fats, high-fat dairy), and limit red/processed meats, while focusing on fiber-rich, whole foods. Key is to control blood sugar spikes by reducing added sugars, sodium, unhealthy fats, and simple carbs.
The International Diabetes Federation officially recognized Type 5 diabetes in 2025. Researchers estimate that it affects 20 to 25 million people worldwide. It mainly affects people in regions where malnutrition is common, like in parts of Asia and Africa.
Severe symptoms
If diabetic hypoglycemia isn't treated, symptoms of low blood sugar get worse. These symptoms can include: Confusion, unusual behavior or both, such as not being able to complete routine tasks. Clumsiness or loss of coordination.
Common signs and symptoms include:
Problems in concentration, logical thought and speech. Loss of desire to participate. Increased sensitivities. Decline in Personal Care.
Anxiety—feelings of worry, fear, or being on edge—is how your mind and body react to stress. People with diabetes are 20% more likely than those without diabetes to have anxiety. Managing a long-term condition like diabetes is a major source of anxiety for some.
High blood sugar can damage blood vessels in the eyes, which can cause diabetic retinopathy and eventually blindness. Diabetic retinopathy is the leading cause of blindness in adults ages 20-74, according to the National Eye Institute. Uncontrolled diabetes also can lead to glaucoma and cataracts.
Someone who is hypoglycaemic (having a low blood sugar diabetic emergency) may have symptoms including:
Avoid sugary drinks whenever possible because not only can they raise blood sugar levels, but they can also contribute many calories to the recommended daily calorie intake.
Examples of the worst foods for diabetics include:
Protein-rich foods like eggs can play an important role in regulating blood sugar levels for people with diabetes. Plus, eggs contain many essential vitamins and minerals, and have just 80 calories each.
Certain supplements like St. John's wort, vitamin E, and niacin can affect glucose levels and may interact with certain medications.
Significant and sustained weight loss—for example, in the range of 10 kg (about 22 pounds) as shown in some studies—is the most important factor. Studies in which participants lost small amounts of weight have shown lower rates of type 2 diabetes remission.
Diabetes can damage your eyes over time and cause vision loss or blindness. Managing your diabetes can help to prevent or delay eye problems. Regular eye exams help to diagnose eye problems early so you can get treatment and protect your eyesight.
Prediabetes means that your blood glucose, or blood sugar, levels are higher than normal but not high enough to be called diabetes. Glucose comes from the foods you eat.
Historical Context of the Cardinal Signs
For centuries, doctors have known about the 4 Ps of diabetes. Polyuria, or too much urine, was one of the first signs noticed. “The disease diabetes is a syndrome characterized by the four cardinal signs: polyuria, polydipsia, polyphagia, and weight loss.”
Symptoms of hyperglycaemia
It's estimated that one in two people. View Source with type 2 diabetes have sleep problems due to unstable blood sugar levels and accompanying diabetes-related symptoms, High blood sugar (hyperglycemia) and low blood sugar (hypoglycemia) during the night can lead to insomnia and next-day fatigue.