Hypothyroidism and Depression: What They Mean for Your Health

Although hypothyroidism and depression are distinct diseases, they are interconnected in many people's lives. Sometimes depression is the first indication that a person's thyroid is underactive (hypothyroid).

If your doctor has diagnosed you with hypothyroidism, this means that your thyroid (a butterfly-shaped gland in the lower part of the neck) is secreting insufficient amounts of thyroid hormone, which, in turn, could interfere with the functioning of virtually every organ, tissue, and cell in the body. But because of an overlap of some symptoms of hypothyroidism and depression, doctors and patients may overlook the possibility that a depressed patient could actually have an underactive thyroid as well. In those cases, the person's depressive symptoms could be caused by hypothyroidism itself.

If you have hypothyroidism, you may have symptoms -- such as fatigue, lethargy, difficulty concentrating, and excessive sleepiness -- that may lead to feelings of depression and the extreme sadness and despair that can accompany it. At the same time, you could have other symptoms commonly associated with an underactive thyroid, including:

• A slower heart rate
• Oversensitivity to cold
• Joint or muscle pain or cramps
• Tingling in the hands and fingers
• Vague aches and pains
• Modest weight gain
• Constipation

Linking Hypothyroidism and Depression

Depression is more significant in people with hypothyroidism than those without thyroid problems. To help doctors determine whether depression is actually caused by or associated with hypothyroidism, depressed patients need to be screened for thyroid disorders. If hypothyroidism is present, diagnostic blood tests can confirm this diagnosis, specifically showing a low level of thyroxine (a thyroid hormone) and a high level of thyroid-stimulating hormone (TSH).

Studies show that if you have both hypothyroidism and depression, rather than relying on antidepressant drugs, your depressive symptoms may improve with thyroid-replacement medications such as triiodothyronine (also called T3) and/or thyroxine (T4), which are the two major thyroid hormones in the body. In people with hypothyroidism and depression, thyroid-replacement drugs may not only relieve the feelings of depression, but also boost the effectiveness of antidepressant drugs. When thyroid pills lower TSH levels to the normal range, the symptoms of depression often subside.

Hypothyroidism and Depression: Research Results

Recent studies have helped identify the optimal management of hypothyroidism and depression. In one report that pooled data from six previous studies, the use of T3 was found to more rapidly improve patient response to tricyclic antidepressants, particularly when T3 was added early in the course of antidepressant therapy. Research also showed that women with hypothyroidism and depression were more likely than men to benefit from this approach.

Other types of antidepressants -- including the popular SSRIs (selective serotonin reuptake inhibitors) like Prozac and Zoloft -- have not been as well studied in people with low thyroid levels, but there is some evidence that these medications could provide significant benefits for patients with hypothyroidism and depression.

Getting Help for Hypothyroidism and Depression

If you're feeling depressed, see your doctor. Because both hypothyroidism and depression can be treated successfully, a proper diagnosis -- including blood tests to measure thyroid hormone production -- is an important first step toward effective management. If symptoms that are associated with hypothyroidism and depression worsen, consult your doctor immediately.