Depression, the Thyroid, and Hormones
What Causes Thyroid Disease?
There are many different reasons why either hyperthyroidism or hypothyroidism might develop. Currently, about 20 million Americans have some form of thyroid disease. People of all ages and races can get thyroid disease. Some babies born with a non-functioning thyroid gland may have thyroid disease from the beginning of life. Women are five to eight times more likely than men to have thyroid problems.
Hypothyroidism may be caused by:
- thyroiditis, an inflammation of the thyroid gland that can affect the level of thyroid hormone production
- Hashimoto's thyroiditis, a painless and hereditary immune system disease
- post-partum thyroiditis, which occurs in five to nine percent of women who have given birth and is usually temporary
Hypothyroidism can also be a side effect of certain drugs, such as lithium and amiodarone, and by iodine deficiency. The thyroid gland uses iodine to make hormones. Iodine deficiency is not a problem in the United States because of the use of iodized salt. However, iodine deficiency is a problem worldwide.
Hyperthyroidism may be caused by:
- Graves' disease, an enlarged thyroid gland (also called diffuse toxic goiter)
- nodules that may form in the thyroid and may cause it to be overactive
- thyroiditis, an inflammation of the thyroid gland that can cause the release of stored hormones (If thyroiditis causes all the hormones to be released, hypothyroidism can follow.)
- excessive iodine, which might be found in certain drugs and some cough syrups
How Is Thyroid Disease Treated?
The goal of treatment for any thyroid disorder is to restore normal blood levels of thyroid hormone. Hypothyroidism is treated with the drug levothyroxine or triiodothyronine.
- Brand names for levothyroxine are Synthroid, Unithroid, Levoxyl, and Levothroid. Levothyroxine is a synthetic hormone that replaces missing thyroid hormone in the body.
- The brand name for triiodothyronine is Cytomel.
- Sometimes the combination of levothyroxine and triiodothyronine is prescribed as two separate pills or, more rarely, as a single pill called liotrix (brand name Thyrolar).
Hyperthyroidism is generally more difficult to treat. That's because it requires the normalization of thyroid hormone production. Treatment might involve drug therapy to block hormone output. Or it might involve radioactive iodine treatment to disable the thyroid. Surgery may be used to remove some or all of the thyroid gland.
Treatment with radioactive iodine, the most common therapy, often causes hypothyroidism. So levothyroxine is used following treatment in order to normalize hormone levels.