Thyroid Dysfunction and Depression

Clinical Presentation and Diagnosis

• Overt hypothyroidism produces symptoms nearly identical to major depression, including fatigue, poor concentration, disturbed sleep, and cognitive difficulties, in patients with Major Depressive Disorder 1, 2
• Thyroid hormone receptors are widely expressed throughout the limbic system and brain regions controlling mood regulation, creating a direct physiological pathway for thyroid dysfunction to manifest as depression 3, 4

Treatment and Management

• Triiodothyronine (T3) has been successfully used as augmentation therapy in depressed patients resistant to first-line antidepressants 5
• If TSH is elevated, measure free T4 and free T3 to distinguish subclinical from overt hypothyroidism, according to clinical guidelines from the American College of Endocrinology 4