Source: DGNews  |  Posted 3 years ago

By Judith Moser, MD

BARCELONA, Spain -- September 4, 2008 -- In patients who receive antipsychotic medication, levels of free thyroxine and free triiodothyronine show significant decreases that may affect thyroid hormone functional activity in some tissues, such as the liver, according to results of a study presented here at the 21st European College of Neuropsychopharmacology Congress (ECNP).

Dysfunction of the thyroid gland is frequently associated with mental disorders including psychoses, but most schizophrenic patients are euthyroid with normal basal concentrations of thyroid stimulating hormone (TSH) levels.

Several studies have reported elevated serum concentrations of thyroxine and/or reverse triiodothyronine in the acute phase of schizophrenia. As the data show, these abnormalities usually resolve with recovery.

Some evidence has shown that pharmacological therapy, including antipsychotics, also may affect the functioning of the thyroid axis.

"We performed a study to evaluate the effects of a treatment with antipsychotic medication on thyroid hormone concentrations," explained study investigator Vesta Steiblienè, MD, Institute of Psychophysiology and Rehabilitation of the Kaunas University of Medicine, Palanga, Lithuania, in a poster presentation on September 2.

The study also evaluated the effects of changes in thyroid hormones on the functional state of some tissues, such as the pituitary gland and liver, evident by changes in TSH and sex hormone binding globulin secretion.

The researchers obtained blood samples from 83 consecutive patients aged 18 to 77 years and diagnosed with endogenous psychotic disorder. Samples were gathered on 2 occasions, at the time of psychiatric admission and at discharge. Concentrations of thyroid peroxidase antibodies also were measured at admission.

All patients received a treatment with antipsychotic medications, including typical and atypical antipsychotics.

As the measurements showed, 9 participants had increased levels of thyroid peroxidase indicating autoimmune thyroiditis.

"Significant changes in thyroid hormone concentrations were found after the treatment with the antipsychotic medication," Dr. Steiblienè reported.

Free T4 concentrations decreased from 17.5 to 16.7 pmol/L (P = .022), and free T3 concentrations decreased from 5.0 to 4.3 pmol/L (P < .001).

The pituitary response to changes in thyroid hormone concentrations was insignificant, but the liver response was substantial, with a significant decrease in sex hormone binding globulin concentrations in both men and women.

Dr. Steiblienè concluded that these findings should be taken into account, especially in the treatment of schizophrenic patients who are simultaneously affected by thyroid problems.

[Presentation title: Effects of Treatment With Antipsychotic Medications on Thyroid Hormone Concentrations. Abstract P3c015]