Association between Thyroid stimulating hormone levels and suicide attempts in Chinese patients with first-episode Drug-naïve major depressive disorder

Abstract Objective Thyroid dysfunction is commonly observed in patients diagnosed with major depressive disorder (MDD).Thyroid function can frequently be accompanied by fluctuations in Thyroid stimulating hormone(TSH) levels.However,the association between TSH levels and suicide attempts (SA) in patients with first-episode drug-naïve (FEDN) MDD remains poorly elucidated. The purpose of this study was to probe into the relationship between TSH levels and SA in a Chinese population with FEDN MDD. Methods A total of 1718 FEDN MDD patients(aged 18 to 60 years) were recruited at the psychiatric outpatient department of the First Hospital of Shanxi Medical University (Taiyuan, Shanxi Province, China) between September 2016 and December 2018. Their socio-demographic characteristics and serum levels of thyroid hormones were acquired. The history of suicide attempts was corroborated by conversational interviews and consultation with the patients' family members. Depressive and anxiety symptoms were assessed by the 17-item Hamilton Rating Scale (HAMD-17) and Hamilton Anxiety Scale (HAMA) respectively .Multivariable logistic regression analysis was used to estimate the association between TSH levels and the risk of SA. Interaction and stratified analyses were performed based on gender, education, marital status, comorbid anxiety, and psychotic symptoms.The threshold effects were tested using a two-piecewise linear regression models. Result An independent and positive correlation was found between TSH levels and SA in patients with FEDN MDD in the multivariable logistic regression model after adjusting for covariates (OR = 1.09, 95% CI: 1.01–1.17;p<0.05). The smoothing plot illustrated a nonlinear association between SA and TSH levels, with 5.43 (ulU/ml) serving as the TSH level's inflection point. TSH levels and SA exhibited an elevated correlation on the right side of the inflection point (OR = 1.21, 95%CI: 1.08 to 1.36, P < 0.001), while no statistically significant relationship was observed on the left side (OR = 0.94, 95%CI: 0.82 to 1.07, P = 0.339). Conclusions Our study indicated a nonlinear TSH-SA association in FEDN MDD patients.This finding may offer crucial insights into developing effective therapeutic options aimed at suicide prevention in individuals suffering from depression.