FT4 and TSH, relation to diagnoses in an unselected psychiatric acute-ward population, and change during acute psychiatric admission

BACKGROUND: Alteration in thyroid activity is a well-known cause of symptoms mimicking psychiatric disorders. There are reports on altered levels of thyroid hormones in patients with certain psychiatric disorders compared to healthy controls; still, the magnitude and importance of the phenomenon is not known. We wanted to explore the level of thyroid hormones in different diagnostic groups in an acute-psychiatric population. We also wanted to follow any change during their stay. METHODS: Patients aged 18 years and older admitted to a closed, psychiatric inpatient ward were eligible if giving informed consent. For 539 patients representing all main psychiatric diagnostic groups and with equal gender distribution, data for FT4 were available for 539 patients, and data for TSH were available from 538 patients at admittance. For 239 patients, data for FT4 were available at both admittance and discharge, and the corresponding number for TSH was 236 patients. RESULTS: A significantly higher share of patients had higher levels of FT4 and TSH at admittance than expected for healthy individuals. No significant effect of gender or most diagnostic groups was seen. For female patients with substance-use disorder (SUD), the level of TSH was significantly lower than that for all other diagnostic groups. No other difference in the levels of FT4 and TSH was seen between the main diagnostic groups, and the effect in SUD was not seen in males. For the population with available markers at both admittance and discharge, in total, there was a significant reduction of FT4 from admittance to discharge, not followed by any change in TSH. CONCLUSIONS: In acutely admitted psychiatric patients there seems to be an increased FT4 and TSH. FT4 is normalized during the inpatient stay independently of TSH. This indicates somatic effects of psychiatric stress that may be of clinical importance and the phenomenon should be further explored. Mainly different diagnostic groups did not differ in level of FT4 and TSH. Thus future studies on thyroid activity in psychiatric patients should focus on function and level of stress and suffering rather than diagnostic groups. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12888-018-1819-3) contains supplementary material, which is available to authorized users.