Revisiting Thyroid Function in Patients Undergoing Electroconvulsive Therapy for Severe or Treatment-Resistant...

Area of Science:

• Neuroendocrinology
• Psychiatry
• Clinical Medicine

Background:

• Limited evidence exists on thyroid function tests (TFTs) in euthyroid individuals with severe or treatment-resistant depression.
• Investigating TFTs in euthyroid patients undergoing electroconvulsive therapy (ECT) is crucial for understanding depression.
• Identifying subgroups with distinct thyroid function patterns may offer new insights.

Purpose of the Study:

• To investigate TFTs in euthyroid patients with depression receiving ECT.
• To evaluate associations between TFTs, ECT response, and depression severity.
• To explore potential clinically meaningful subgroups based on thyroid function.

Main Methods:

• Retrospective cohort study of 107 inpatients receiving ECT for severe/treatment-resistant depression.
• Analysis of 76 euthyroid patients, including clinical data, Hamilton Depression Rating Scale (HAMD) scores, and TFTs (TSH, free-T3, free-T4).
• Logistic regression, multiple linear regression, and unsupervised hierarchical cluster analyses were performed.

Main Results:

• TFT results were not significantly associated with ECT response in euthyroid patients.
• Baseline HAMD scores positively correlated with free-T4 levels (β = 0.797, p = 0.001).
• Hierarchical clustering identified two subgroups; one with male sex, psychotic features, and MDD diagnosis showed lower TSH levels.

Conclusions:

• Subtle variations in TFTs within the normal range are linked to depression severity and clinical phenotypes, not ECT response.
• Thyroid hormone variability may reflect state-related neuroendocrine patterns in severe depression.
• Further prospective studies are needed to clarify the clinical significance of thyroid function variability in depression.