Many people with lupus also suffer from thyroid problems. A thyroid problem will affect the brain, kidney, heart, liver, and skin. If you have a progressive attack of the thyroid gland, this leads to underactive thyroid which causes depression, fatigue, and weight gain. Underactive thyroid is treated with thyroid hormone therapy. The body may produce too much thyroid hormones leading to heart palpitations, weight loss, anxiety and mood swings, which is a condition called overactive thyroid. It may be treated with radioactive iodine.