Thyroid Hormones and Mood Disorders

Thyroid hormone deficiency or excess may cause emotional disturbances and mood disorders, encompassing major depressive syndromes and bipolar disorders, along with various other neuropsychiatric conditions, some of which may have developmental origins. In particular, profound long-term untreated hypothyroidism can culminate in severe psychosis, historically referred to as myxedema madness. Addressing the underlying thyroid condition typically proves highly effective in rectifying the associated brain disorder. Subclinical thyroid diseases have also been implicated in emotional and cognitive disorders, prompting inquiry into the optimal treatment window. Moreover, thyroid hormones have demonstrated potential in expediting or augmenting the effects of standard mood disorder treatments in euthyroid patients, hinting at a baseline state of localized cerebral hypothyroidism with an uncertain pathogenesis, potentially remediable through high doses of thyroid hormones.