Thyroid function in Exhaustion Disorder: Higher prevalence of subclinical hypothyroidism

Abstract

Title: Thyroid function in Exhaustion Disorder: Higher prevalence of subclinical hypothyroidism

Author, Year: Christina Hindgren, 2012

Institution, City, County: Medicine, Gothenburg, Sweden

Background: Exhaustion Disorder (ED) is a common illness characterized by reduced mental energy caused by stress. In order to increase understanding and improve treatments for the illness, research is needed to investigate its pathophysiology, including potential endocrine dysfunction.

Aims: The general aims were to investigate if thyroid function is associated with ED and if there is a difference in thyroid function between patients with only ED and patients with Major Depression (MD) co-morbid to ED.

Methods: The study was of a case-control, cross-sectional design. Thyroid function was assessed by measuring serum thyroid-stimulating hormone (TSH) and free thyroxine (fT4) in 350 ED patients and 200 controls.

Results: There was no difference in TSH and fT4 between ED patients and healthy controls. Neither were there any differences in TSH and fT4 between the three groups ED with MD, ED without MD and controls. However, the prevalence of subclinical hypothyroidism was higher in ED patients compared to healthy controls. There was no difference between ED patients and controls in early thyroid failure defined as TSH above 2 mU/l.

Conclusions: ED does not seem to be associated with thyroid dysfunction in general. However, subclinical hypothyroidism was more prevalent in ED patients compared with controls. ED patients with subclinical hypothyroidism may have started to develop thyroid failure prior or parallel to ED, which may have contributed to the symptoms seen in ED. Thus this could explanation the higher prevalence of subclinical hypothyroidism found in ED patients. It is also possible that subclinical hypothyroidism is a negative prognostic factor for treatment of ED. Future randomised controlled studies on treatment outcome is needed to clarify if ED patients with subclinical hypothyroidism will benefit from thyroid hormone therapy.