The goal of this clinical trial is to evaluate the efficacy and safety of sertraline combined with Lactobacillus crispatus in adolescents aged 12-18 years with major depressive disorder. The main question it aims to answer is: Whether sertraline combined with Lactobacillus crispatus is superior to sertraline combined with placebo in reducing depressive symptoms and improving emotional symptoms in adolescents with depression.
If there is a comparison group: Researchers will compare sertraline combined with Lactobacillus crispatus with sertraline combined with placebo ( look-alike substance that contains no probiotics) to determine whether the addition of Lactobacillus crispatus provides greater therapeutic benefit in adolescents with depression.
Participants will: 1. Receive sertraline combined with Lactobacillus crispatus or sertraline combined with placebo for 8 weeks; 2. Attend clinic visits every 4 weeks for clinical assessments and safety monitoring
Aged 12-18 years
Meets DSM-5 criteria for major depressive disorder (MDD) and is currently in a depressive episode according to the Kiddie Schedule for Affective Disorders and Schizophrenia - Present and Lifetime Version (K-SADS-PL) interviews
Child Depression Rating Scale-Revised (CDRS-R) score ≥40 at baseline
Clinical Global Impression Scale (CGI-S) score ≥ 4 at baseline
Presence of any comorbid psychiatric disorder according to DSM-5, other than anxiety disorders
MDD with psychotic symptoms
Young Mania Rating Scale (YMRS) >13 at baseline
History of neurological disorders (e.g., epilepsy, traumatic brain injury), or the presence of serious physical illnesses (e.g., thyroid disease, lupus erythematosus, diabetes mellitus, clinically significant pulmonary, hepatic, or renal impairment, or major trauma)