Hyperthyroxinemia in patients with acute psychiatric disorders.

Area of Science:

• Endocrinology
• Psychiatry
• Clinical Chemistry

Background:

• Thyroid dysfunction is frequently observed in patients with acute psychiatric disorders.
• Elevated thyroid hormone levels, specifically serum thyroxine (T4) and free thyroxine index (FTI), are noted in a significant percentage of psychiatric admissions.

Purpose of the Study:

• To investigate the longitudinal changes in thyroid function tests in patients admitted to an acute psychiatric disorders unit.
• To characterize the patterns of serum thyroxine (T4), free thyroxine index (FTI), free T4, and triiodothyronine (T3) over time in a subset of patients with initial thyroid hormone elevations.

Main Methods:

• Thyroid function tests including serum T4, FTI, free T4, and T3 were measured in 645 patients.
• A subgroup of 22 patients with initially elevated FTI underwent serial testing.
• Thyrotropin-releasing hormone (TRH) stimulation tests were performed serially.

Main Results:

• Thirty-three percent of patients had elevated T4, and 18 percent had elevated FTI.
• In the study group (n=22), serum T4, FTI, and free T4 levels significantly decreased over the observation period (p < 0.001 for all).
• Serum T3 levels showed variable changes, falling in 17 patients and rising in five.
• Serial TRH tests revealed both flat and normal responses across different psychiatric diagnoses and thyroid disease activity stages.

Conclusions:

• Initial elevations in T4 and FTI in psychiatric patients are often transient and normalize over time.
• The dynamic changes in thyroid hormones suggest complex interactions between psychiatric illness and thyroid regulation.
• TRH stimulation tests do not show a consistent pattern in this patient population, highlighting the heterogeneity of thyroid axis function in psychiatric disorders.