Graves' disease is an autoimmune disorder that causes hyperthyroidism or overactivity of the thyroid gland. It is most common in women over age 20. Symptoms include anxiety, rapid heartbeat, eye problems, weight loss and more. Graves' disease occurs when the immune system produces antibodies that mimic the effects of thyroid stimulating hormone, causing the thyroid to overproduce hormones. Treatments include beta blockers, antithyroid medications, radioactive iodine or surgery to destroy the thyroid gland. While treatments are usually effective, they can sometimes lead to hypothyroidism if not managed correctly.