Depression, the Thyroid, and Hormones

Medically Reviewed by Jennifer Robinson, MD on April 26, 2023
5 min read

The thyroid gland produces and regulates thyroid hormones. These hormones can affect energy levels, mood, even weight. They can also be factors in depression. Read on to find out what causes thyroid-related depression and how it's treated.

Hormones are substances produced by the endocrine glands that have a tremendous effect on bodily processes. The glands in the endocrine system influence growth and development, mood, sexual function, reproduction, and metabolism.

Levels of certain hormones, such as those produced by the thyroid gland, can be factors in depression. In addition, some symptoms of depression are associated with thyroid conditions. The same is true about conditions related to the menstrual cycle, such as premenstrual syndrome (PMS), perimenopause, and menopause.

Because there is this connection between depression symptoms and other medical conditions, blood tests are often ordered to avoid a misdiagnosis. It is important to note that you can have both depression and thyroid conditions at the same time. It is also possible to have depression and menstruation-related symptoms.

Thyroid gland hormones can affect food metabolism, mood, and sexual function. When the thyroid produces too much hormone, the body uses energy faster than it should. This condition, overactive thyroid, is called hyperthyroidism. Symptoms that may indicate hyperthyroidism include:

  • enlarged thyroid gland
  • inability to tolerate heat
  • infrequent, scant menstrual periods
  • irritability or nervousness
  • rapid heartbeat
  • muscle weakness or tremors
  • sleep disturbances
  • more frequent bowel movements
  • weight loss

When the thyroid gland does not produce enough hormone, the body uses energy at a slower pace than it should. This condition, underactive thyroid, is called hypothyroidism. Symptoms that may indicate hypothyroidism include:

  • dry, coarse skin and hair
  • fatigue
  • forgetfulness
  • irregular menstrual periods
  • hoarse voice
  • inability to tolerate cold
  • weight gain
  • enlargement of the thyroid gland (goiter)

Some of these symptoms -- fatigue, irritability, weight changes, and sleep problems -- are symptoms that may also mimic depression.

Your doctor may order blood tests to determine levels of certain hormones, including:

  • thyroid stimulating hormone (TSH, which is released by the pituitary gland)
  • triiodothyronine (T3)
  • thyroxine (T4)

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
  • postpartum 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 amiodarone and lithium, 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

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.

Hyperthyroidism is generally more difficult to treat. That's because it requires the normalization of overactive 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.

First, as noted earlier, women are more likely than men to develop thyroid conditions. Women are also more likely than men to be diagnosed with depression. Because of biology, women are more vulnerable to hormone-induced depression.

The process of menstruation involves fluctuations in the levels of estrogen and other hormones. Some women experience depression-related symptoms such as sadness, irritability, and fatigue prior to menstruation. These symptoms are part of the premenstrual syndrome, or PMS. A more severe case of emotional problems related to menstruation is known as premenstrual dysphoric disorder (PMDD).

When pregnant, women are subject to physical and emotional changes caused in part by changes in hormones. After pregnancy, women experience a huge shift in hormone levels. This shift is a likely cause of the "baby blues," a mild type of depression that immediately follows childbirth in up to about 80% of women and generally resolves quickly. A more severe form of depression -- post-partum depression -- could also result less often (in about 10-20% of new mothers). Postpartum depression can be treated with brexanolone (Zulresso) which is a synthetic form of the progesterone derivative allopregnanolone.

When women get older and move out of child-bearing years, they experience changes in hormone levels. These changes happen during perimenopause and menopause. Symptoms that occur during this time of life could include fatigue, sleep disturbances, weight gain, and skin changes.

Women who experience symptoms of depression need treatment. Treating depression in mothers is important for both mothers and children. Treatment of hormone-related depression may include the same things that work for depression in general -- talk therapy, strong support networks, and antidepressant medications.