Endocrine Abstracts

Introduction

Today, it is well recognized that disturbances in thyroid function may significantly affect mental status including emotion and cognition. Several studies have demonstrated the existence of a relationship between depression and hypothyroidism, although there is still no clear explanation of the pathophysiology that causes this association.

Objectives

To assess whether there is a higher prevalence of depression among patients with hypothyroidism and whether it is correlated with laboratory parameters such as TSH, free T4 or the levels of anti-peroxidase (TPO) and anti-thyroglobulin antibodies.

Methods

We collected the medical and psychiatric history and laboratory tests of 200 patients with autoimmune hypothyroidism treated in our hospital (Hospital Clínico Lozano Blesa, in Zaragoza; Spain). Student’s T test was used for statistical analysis.

Results

A high prevalence of depression was observed among patients with autoimmune hypothyroidism (46.5%), in addition, higher mean values ​​of anti-TPO antibodies have been obtained in patients with depression (552.87 IU/ml versus 337.12 IU/ml, P = 0.015), as well as anti-thyroglobulin antibodies (371.52 IU/ml vs. 135.27 IU/ml, P = 0.034) and TSH (20.55 mU/l vs. 9.31 mU/l P = 0.012). There were no differences between the FT4 values ​​of both groups.

Discussion and conclusion

There is a significant prevalence of depressive symptoms among hypothyroid patients, being present in almost half of the individuals studied, as well as higher levels of TSH and anti-TPO and antithyroglobulin antibodies in subjects diagnosed with depression, all of that according to the published data in previous studies. Therefore, it could be interesting to quantify thyroid hormones in those patients who present with symptoms of depression, especially those who are more refractory to antidepressant treatment. However, the mechanisms underlying the interaction between thyroid function and depression remain to be clarified and a causal relationship between the two cannot be established yet, so more studies are needed to clarify the specific reason for this association. Moreover, further studies are required to determine if thyroid-related genes can influence well-being in subjects that are not on thyroid hormone replacement and if thyroid hormones may be beneficial in these subjects if they are not responding to standard antidepressant therapies.