TSH and T4 Levels in a Cohort of Depressive Patients

Depression is a significant contributor to the overall burden of disease on a global scale. Thyroid hormones thyroxine (T4) and triiodothyronine (T3) have been shown to play a critical role in the development and normal function of the brain. It has been suggested that dysregulation of thyroid function could be associated with depression, especially hypothyroidism, but not all studies support this hypothesis. We enrolled a cohort of 96 subjects with major depressive disorder and tested TSH and FT4 levels for 80 of them in order to assess the status of the hypothalamic-pituitary-thyroid axis (HPT). We found 7 cases (8.75% of the tested) of subclinical hyperthyroidism and 1 case (1.25%) of overt hyperthyroidism. While we did not find supporting evidence for association between TSH and FT4 levels and depression, our findings question whether screening depressive patients for HPT axis anomalies could be clinically relevant, if anything, in a regional context.