Thyroid Disease and Mental Disorders: Cause and Effect or Only comorbidity?

Robertas Bunevičius; Arthur J. Prange Jr


Curr Opin Psychiatry. 2010;23(4):363-368. 

In This Article

Thyroid Autoimmunity

The major cause of disturbed thyroid hormone secretion is autoimmune thyroid disease (AITD), when autoantibodies against the normal elements of the thyroid axis are produced. Biopsy and autopsy results show that up to 40% of women have AITD. There are two major forms of AITD: Graves' disease, a common cause of hyperthyroidism, and autoimmune thyroiditis, a common cause of hypothyroidism.[35] In community studies, relationships between thyroid autoimmunity and mental disorders are inconsistent. One large study[36] found no relationship between the presence of thyroid antibodies and anxiety or depression. However, four other studies reported that thyroid autoimmunity is related to anxiety or depression: a community sample,[37] a primary care sample,[38] a large cohort of pregnant women,[17] and a large cohort of perimenopausal women.[39] Moreover, patients with euthyroid Graves' disease display more mood and anxiety disorders than patients without autoimmune disease.[20] Finally, high titers of thyroid antibodies have been reported in psychiatric patients with affective disorders.[40]

Involvement of AITD in brain functioning has been found in neuroimaging studies. Euthyroid patients with autoimmune thyroiditis, compared with euthyroid patients without autoimmune thyroiditis, showed more brain perfusion abnormalities as well as more severe symptoms of anxiety and depression.[41] Neuroimaging abnormalities were similar to those observed in Hashimoto's encephalopathy, an infrequent but life-threatening acute brain syndrome caused by AITD. These findings suggest a higher than expected involvement of the brain in AITD.[42] Patients with AITD have increased antibody reactivity against brain tissue and gangliosides,[43] suggesting that thyroid autoimmunity may sometimes be a part of a larger autoimmune process. On the contrary, thyroid antibodies may directly affect brain functioning. For example, in Graves' disease, the thyrotropin receptor becomes an antigen, and its excessive stimulation by thyrotropin receptor antibodies increases D2 activity and excessive local production of T3 in tissues that are rich in these receptors, especially in cerebral cortex and hippocampus.[20]


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