Insulin toxicity, also known as insulin overdose, occurs when an individual receives an excessive amount of insulin, leading to abnormally low blood sugar levels (hypoglycemia). Symptoms of insulin toxicity include confusion, sweating, tremors, seizures, and even loss of consciousness. In severe cases, it can lead to coma and death. Causes of insulin toxicity include incorrect insulin dosing, insulin pump malfunctions, and insulin resistance. Treatment involves immediate administration of glucose to raise blood sugar levels and potentially glucagon injection if the person is unconscious. Prevention includes proper insulin dosing, monitoring blood sugar levels, and awareness of symptoms of hypoglycemia. 

1. Hypoglycemia: Long-term insulin use can increase the risk of hypoglycemia, which is a potentially dangerous condition characterized by abnormally low blood sugar levels.

2. Weight gain: Insulin therapy can lead to weight gain, which increases the risk of developing other health problems, such as cardiovascular disease and type 2 diabetes.

3. Insulin resistance: Long-term use of insulin can lead to insulin resistance, which reduces the effectiveness of insulin and can lead to higher blood sugar levels.

4. Allergic reactions: Some people may develop an allergic reaction to insulin, which can cause symptoms such as hives, rash, and difficulty breathing.

5. Lipodystrophy: Long-term insulin use can cause lipodystrophy, a condition characterized by the loss or redistribution of body fat, which can cause lumps or indentations at the injection site.

6. Increased risk of cancer: Some studies suggest that long-term insulin use may increase the risk of certain types of cancer, such as breast, colon, and pancreatic cancer.

7. Infection: Injection sites can become infected, leading to abscesses or cellulitis, which can be serious and require medical treatment.

8. Diabetic retinopathy: Long-term insulin use can increase the risk of diabetic retinopathy, a condition that can lead to vision loss or blindness.

9. Nerve damage: Long-term insulin use can increase the risk of nerve damage, which can cause symptoms such as numbness, tingling, and pain in the hands and feet.

10. Psychological effects: Long-term insulin use can have psychological effects, such as anxiety, depression, and fear of hypoglycemia. These can have a significant impact on a person's quality of life and overall well-being.