Abstract: Major Depressive Disorder (MDD) and subclinical hypothyroidism (SCH) frequently co-occur, and their relationship involves overlapping clinical features and intertwined pathophysiological mechanisms. SCH –defined by elevated thyroid-stimulating hormone (TSH) with normal thyroid hormone levels – is common, affecting roughly 3–8% of the general population (up to 20% in the elderly). Depression is a well recognized neuropsychiatric manifestation of thyroid dysfunction. Recent studies in the past decade suggest that even mild thyroid impairment may influence mood disorders: patients with SCH have an increased prevalence of depressive symptoms, although findings are mixed regarding causality. Biochemical pathways linking the hypothalamic-pituitary-thyroid (HPT) axis and monoamine systems provide a possible mechanism for this association. Clinically, the symptom overlap between MDD and SCH can complicate diagnosis, underscoring the importance of thyroid function screening in depressive patients. Treatment interactions are also significant – untreated SCH may hinder antidepressant response, whereas thyroid hormone supplementation (levothyroxine or liothyronine) can augment depression treatment in select cases. This concise review synthesizes recent evidence on the complex MDD–SCH relationship, emphasizing biochemical links, diagnostic challenges, and treatment implications for improved clinical decision-making.
Keywords: Major Depressive Disorder, subclinical hypothyroidism, relationship, phycology.
Title: Major Depressive Disorder and Subclinical Hypothyroidism: A Complex Relationship with Clinical Implications
Author: Dr. Moosa Jeded S Alenazi
International Journal of Healthcare Sciences
ISSN 2348-5728 (Online)
Vol. 13, Issue 1, April 2025 - September 2025
Page No: 313-318
Research Publish Journals
Website: www.researchpublish.com
Published Date: 25-June-2025
