Comparison of thyroid function in different emotional states of drug-naïve patients with bipolar disorder

Previous studies have shown that bipolar disorder is closely related to thyroid dysfunction. Psychiatric drugs have a large or small effect on thyroid function, and thyroid hormone levels can also affect the effect of drug treatment. Therefore, the purpose of this study is assessment the thyroid function of drug-naive bipolar disorder across different mood states, with the expectation of providing support for treatment options.

The present study is a cross-sectional study. Patients diagnosed with bipolar disorder according to the International Classification of Diseases diagnostic Criteria, Edition 10 (ICD 10) and who had never received medication were included in the study. The Montgomery Depression Scale (MADRS) was used to assess depressive symptoms and the Young Mania Rating Scale (YMRS) for manic symptoms. Thyroid function indicators include thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), total triiodothyronine (TT3), free thyroxine (FT4), and total thyroxine (TT4). Levels of TSH, TT4, FT4, TT3, and FT3 were measured within 48 h of hospitalization, between 06:00 and 08:00.

The data analysis finally covered the data of 291 subjects (136 in a bipolar manic group, 128 in a bipolar depressive group, and 27 in a bipolar mixed group), including 140 males and 151 females, with an average age of 27.38 ± 8.01. There was no significant difference in age, sex, marital status, work status, family history, and course of illness among the manic group, depressive group, and mixed group. The level of FT3, the rate of thyroid hormone increased secretion, and the total abnormality rate of thyroid hormone secretion in the manic group were significantly higher than those in the depressive group.

These findings indicate that thyroid functions were significantly different between depressive and manic episodes in BD patients. In clinical practice, it is necessary to take into account the differences in thyroid hormone levels in patients with BD across different emotional states in choosing drug.