Depression and thyroid function tests

The thyroid hormone plays an important role in regulating the mood and cognitive functions of the body. Studies have revealed that although a majority of the cases of depression are associated with euthyroidism, thyroid dysfunction has commonly been seen associated with depression. The most commonly seen thyroid abnormality in the thyroid patients are raised levothyroxine (T4), decreased tri-iodothyronine (T3), and raised thyrotropin release hormone (TRH) levels, and a blunted thyroid stimulating hormone (TSH) response. A majority of the patients with abnormal thyroid function tests are associated with subclinical hypothyroidism. It is also believed that T3 supplementation, even in the euthyroid patients with depression, is associated with improvement in their depression scores