Antidepressant and Stabilizing Effects of Thyroid Hormone Augmentation in Women’s Mood Disorders

Women are at increased risk for new onsets and recurrences of depressive illness that may occur at puberty, with oral contraceptive use, premenstrual, peripartum and at the perimenopause. Women also may develop thyroid disease during these times of reproductive hormonal change. For patients who develop mood disorders, most studies indicate that thyroid augmentation has the potential to enhance the response to antidepressant medication and to stabilize the mood disorder, particularly in women. Herein, we review the history of using thyroid supplements to enhance antidepressant responses, propose potential mechanisms, and provide selected case reports and prescription guidelines. In sum, thyroid augmentation strategies provide a high likelihood of significant clinical benefit, with relatively minor risks: For treatment-resistant depression, triiodothyronine (T3) (25-50 ug) tends to enhance antidepressant effects more than levothyroxine (T4), works best as an adjunctive agent rather than as monotherapy, is more efficacious in women than in men, and the antidepressant benefits may be observed in the context of euthyroid status. In women prone to rapid-cycling mood disorders, T4 has been shown to stabilize the potentially devastating rapid cycles of mood that occur in this severe form of bipolar illness. The aim of this report is to increase clinician awareness of these treatment strategies to enhance the well-being of women during their lifecycle, as untreated depressions may impair the optimal functioning and quality of life of the woman, deterring her ability to make valuable contributions to her family and society, and potentially leading to increased frequency, severity and more treatment-resistant depressive episodes.