Source: Chest  |  Posted 11 years ago

In women suffering from hypothyroidism, replacing some of the T4 dose with triiodothyronine improves cognition and mood, a new study shows.

The authors treated 11 women suffering from autoimmune thyroiditis and 15 females who had been treated for thyroid cancer with either their usual dose of thyroxine (T4) or with a regimen in which 12.5 ?g of triiodothyronine (T3) replaced 50 ?g T4. After five weeks, patients switched to the other regime for another five weeks.

Substituting T3 for a portion of T4 changed the concentrations of thyroid hormones and thyroid-stimulating hormone (TSH) as well as improving cognition and mood. However, the improvement in mood was greater than that seen in cognition. Some of the mood improvements correlated with changes in TSH and free T4.

Patients treated for thyroid cancer showed a more marked cognitive improvement than those with autoimmune thyroiditis. The authors speculate that this might reflect the cancer patients? greater dependence on exogenous hormone.