Berberine in Treating Negative Symptoms of Schizophrenia: Clinical Efficacy and Mechanisms

The investigators will enroll at least 120 patients with schizophrenia (SZ) meeting the inclusion criteria, randomized 1:1 to either the experimental group receiving antipsychotic medication plus berberine (BBR) or the control group receiving antipsychotic medication plus placebo, for a clinical intervention of 12 weeks. The primary outcome measures will be the change in the Negative Symptom Scale (SANS) total score and the log50 result of the skin nicotine test throughout the 12-week period. Secondary outcome measures include the Positive and Negative Syndrome Scale (PANSS), the Clinical Global Impression scale (CGI), the Calgary Depression Scale for Schizophrenia (CDSS), the Global Assessment of Functioning (GAF), the Extrapyramidal Symptom Rating Scale, and cognitive assessments (MATRICS Consensus Cognitive Battery - MCCB). Other study indicators will involve the collection of sociodemographic and general clinical data. Blood and stool samples will be collected at pre-intervention (baseline), at 12 weeks of intervention, or at study termination. For safety assessments, participants' vital signs will be monitored at baseline, 4 weeks, 8 weeks, and 12 weeks, along with physical parameters (height, weight, blood pressure). Laboratory investigations will include complete blood count, comprehensive biochemical panel, and electrocardiogram (ECG). The Treatment Emergent Symptom Scale (TESS) will be used to assess drug side effects, and any adverse events will be recorded. Ultimately, the collected data will be used to investigate the clinical efficacy and safety of BBR on negative symptoms in SZ, its impact on the gut microbiota and their metabolic small molecules, its effect on peripheral blood inflammatory factors in SZ patients, and the longitudinal and cross-sectional correlations between gut microbiota and their metabolic small molecules, blood parameters, and negative symptoms in SZ patients under BBR treatment. This will facilitate the identification of early predictive biomarkers for BBR efficacy and key gut microbiota targets responsible for improving negative symptoms in SZ.