Prevalence and Clinical Correlates of Suicide Attempts Among Young Patients With Major Depressive Disorder With Subclinical Hypothyroidism: A Cross-Sectional Study.

OBJECTIVE: Depression frequently co-occurs with subclinical hypothyroidism (SCH), but its role in suicide risk among young patients with major depressive disorder (MDD) remains unclear. We investigated suicide attempts (SAs) among a large cohort of young, first-episode drug-naïve (FEDN) patients with MDD and SCH. METHOD: A total of 917 FEDN patients with MDD (351 males and 566 females; mean age = 24.7 ± 5.4 years, range = 18-35 years) were recruited. Sociodemographic, clinical data, and thyroid function parameters were collected from all patients. Anxiety, depression, psychotic symptoms, and overall clinical severity were assessed using the Hamilton Anxiety Rating Scale (HAMA), Hamilton Depression Rating Scale (HAMD), Positive and Negative Syndrome Scale Positive Subscale, and Clinical Global Impression (CGI) scale, respectively. RESULTS: Young MDD patients had an increased prevalence of SCH (56.8%). Among young MDD cases with SCH, SAs were associated with age, marital status, illness duration, and HAMA score; for HAMA score, B = 0.167, OR = 1.182, 95% CI: 1.062-1.315, and p = 0.002. SAs were also associated with thyroid stimulating hormone (TSH) (B = 0.315, OR = 1.371, 95% CI: 1.180-1.592, p < 0.001), thyroid peroxidase antibody (TPOAb) (B = 0.004, OR = 1.004, 95% CI: 1.002-1.006, p < 0.001) and CGI score. Combining HAMA, TSH, and CGI scores differentiated those who attempted suicide from those who did not (area under the curve = 0.792). HAMD, HAMA, TPOAb, TSH, illness duration, age, and marital status were independently related to the number of SAs (p < 0.001). CONCLUSIONS: Young FEDN patients with MDD showed a high prevalence of SCH, and SAs were common among those with comorbid SCH. Clinical characteristics and thyroid function indicators were independently associated with SAs, highlighting the importance of thyroid screening and suicide-risk assessment in young patients with MDD.