Hypothyroidism and Depression

Hypothyroidism is a condition in which the thyroid gland is underactive. The thyroid gland controls the rate of energy production in the body, regulates body temperate and has a profound effect on brain chemistry, mood and the emotions.

Hypothyroidism Symptoms

Symptoms of hypothyroidism (an underactive thyroid gland) include:

  • Depression
  • Fatigue, needing lots of sleep
  • Sensitivity to cold
  • Cold hands and feet
  • Poor concentration and memory
  • Morning headaches
  • Weight gain or inability to lose weight despite normal eating
  • Morning headaches
  • Hoarseness
  • Constipation, chronic digestive problems
  • Low sex drive
  • Swollen face, water retention
  • Dry skin
  • Dry or brittle hair
  • Thinning or loss of hair from the outer part of the eyebrow
  • Muscle cramps
  • Susceptibility to colds and infections
  • Slow wound healing

Take the hypothyroidism test to find out if you could have hypothyroidism. Or, take our 13 depression tests to find out if you could have one of 13 common causes of depression.

How Hypothyroidism Causes Depression

Hypothyroidism causes depression in several different ways. The thyroid controls the rate of glucose metabolism, particularly the uptake of glucose into the cells. The brain is the body's biggest consumer of glucose and when the brain doesn't have enough glucose for fuel, brain function is poor and mental fuzziness, poor memory, poor concentration and depression result. The thyroid controls stomach acid production and when stomach acid is too low, absorption of protein and vital nutrients such as B12, iron and calcium is reduced. This leads to deficiencies in brain chemicals such as serotonin, tyrosine, GABA and endorphins, all of which are produced from protein using a range of vitamins and minerals. In addition, hypothyroidism often leads to adrenal fatigue, with associated fatigue and depression.

Thyroid Function Overview

The pituitary gland controls thyroid activity by releasing Thyroid Stimulating Hormone. The Thyroid gland responds by producing two different kinds of thyroid hormone, T3 and T4. While the thyroid gland mostly produces T4, the body mostly uses T3, so most of the T4 produced by the thyroid gland must be converted to T3 so it can be used by the body. This conversion happens in the liver, the intestines (provided the gut flora are healthy) and to a lesser extent in other cells of the body. A breakdown at any point in this pathway can lead to symptoms of hypothyroidism.

Types of Hypothyroidism

The most common cause of hypothyroidism is Hashimoto's disease, an autoimmune disease in which the body's immune cells attack the thyroid gland. Other causes include poor liver function, digestive problems, pituitary gland problems and excess estrogen.

There are 6 main patterns of hypothyroidism:

  • Primary Hypothyroidism - the thyroid gland itself is underactive and does not produce enough thyroid hormones (T3 and T4). Hashimoto's Thyroiditis in one type of Primary Hypothyroidism.
  • Hypothyroidism Secondary to Pituitary Hypofunction - the pituitary gland is underactive and does not release enough thyroid stimulating hormone. This can be due to adrenal fatigue, post partum depression or inappropriate use of thyroid medications.
  • Thyroid Underconversion - the thyroid gland makes enough T4 but the body doesn't convert enough T4 to T3, the more active form of thyroid hormone. This can happen with adrenal fatigue as high cortisol levels suppress the conversion of T4 to T3, or as a result of chronic infection or inflammation.
  • Thyroid Overconversion and Decreased Thyroid Binding Globulin (TBG) - too much T4 is converted to T3 and the cells develop a resistance to T3. This is caused by elevated levels of testosterone in women, often due to insulin resistance, diabetes or polycystic ovary syndrome.
  • Thyroid Binding Globulin (TBG) Elevation - TBG binds to thyroid hormone and transports it through the bloodstream. The TBG must release the thyroid hormone before it can be used by the cells of the body, and when TBG levels are too high, not enough free thyroid hormone is available to be used by the cells. This is caused by excess estrogen and is common in women taking birth control pills or hormone replacement therapy.
  • Thyroid Resistance - Adrenal fatigue with high cortisol levels causes the cells to become resistant to thyroid hormones.

Diagnosis of Hypothyroidism

Blood tests are commonly used to diagnose hypothyroidism, but these are often used inappropriately. A thyroid test should include tests for at least 5 different substances, but most doctors only order a test for TSH (thyroid stimulating hormone). The problem with this is that TSH levels are only abnormal in Primary Hypothyroidism - in the five other types of hypothyroidism, TSH levels are usually completely normal. Even for Primary Hypothyroidism the TSH test is not always reliable, as there is considerable disagreement as to what a normal level of TSH is. In addition, in Hashimoto's Thyroiditis, TSH levels can fluctuate between high, low and normal as the disease flares up and dies down.

A doctor who is knowledgeable about hypothyroidism will order a range of blood tests including TSH, free T3, free T4, Thyroid Binding Globulin, Thyroid Antibodies and TRH (thyrotropin-releasing hormone); and will make a diagnosis based on all of these measures plus a thorough case history. Hashimoto's Thyroiditis, the most common form of hypothyroidism, is diagnosed using thyroid antibody levels, but because this disease flares up and dies down, multiple tests may be needed.

Saliva tests for adrenal function should also be considered as some kinds of hypothyroidism are caused by adrenal fatigue.

A simple home test can give a good indication as to whether hypothyroidism may be a problem. Use a basal thermometer, which is available in most drug stores, not a fever thermometer. When you wake up, stay in bed and place the thermometer under your armpit for 10 minutes. Do this for at least 3 mornings to get an average temperature. If the average temperate is less than 97.8 degrees Fahrenheit (36.5 degrees Celsius), you may have a thyroid problem and should see a physician for further testing.

Treatment of Hypothyroidism

Treatment varies depending on the type of hypothyroidism and its cause. Synthetic thyroid hormones or glandular thyroid are the most commonly prescribed treatment and are often effective but can exacerbate some types of hypothyroidism. Depending on what type of hypothyroidism you have, you may need to be treated for adrenal fatigue, digestive disorders, liver problems or hypoglycemia, make dietary changes, take particular nutritional supplements or stop the contraceptive pill or hormone therapy. Why Do I Still Have Thyroid Symptoms? When My Lab Tests Are Normal covers the treatment of the various types of hypothyroidism in detail.

Other Causes of Depression

Take our 13 depression tests to find out if you could have any of the other common causes of depression.

Where to Find More Information

Why Do I Still have Thyroid SymptomsWhy Do I Still Have Thyroid Symptoms? When My Lab Tests Are Normal: A Revolutionary Breakthrough In Understanding Hashimoto's Disease and Hypothyroidism