Relationship Between Depression and Thyroid Hormone Levels in Patients with Graves Disease

Objective To explore the relationship between depression and thyroid hormone levels in Graves disease patients. Methods A total of 188 out-patients with Graves disease were enrolled in this study. All patients received the measurements of Zung Self-Rating Depression Scale (SDS) and serum thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) and TSH receptor antibodies (TRAb). Results All the patients were divided into 3 groups: high FT4 level group （n=65）, normal FT4 level group （n=113） and low FT4 level group （n=19）. There were statistically significant difference of SDS scores (P<0.05) in 3 groups, but no significant difference in the occurrence of depression (P>0.05). In Pearson correlation analysis, SDS score was positively correlated with serum FT3 ( r=0.372, P<0.001) and FT4 level ( r=0.288, P<0.001), negatively correlated to serum TSH level but no statistically significant ( r=-0.028, P=0.614). logistic regression analysis showed that TSH （P=0.131）, FT4 （P=0.637）, and FT3 (P=0.208) were not the independent risk factors for the occurrence of depression. Conclusion Although the prevalence of depression is high in Graves disease patients, there is no close correlation between depression and the level of thyroid hormone.