Abstract
OBJECTIVE: This study aimed to investigate the effects of atypical antipsychotic drugs (AAPDs) on changes in body composition and fat distribution characteristics in patients with first-episode schizophrenia (FSCZ) and chronic schizophrenia (CSCZ), as well as to predict their temporal trends. METHODS: A total of 70 inpatients (51 FSCZ, 19 CSCZ) admitted to Tianjin Anding Hospital from January 2023 to June 2024 were enrolled. Body composition indicators, including weight (W), Body Mass Index (BMI), waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), abdominal skinfold thickness (ASF), body fat (BF), body fat percentage (BFP), and visceral fat area (VFA) were measured at baseline and every 4 weeks over a 12-week period. A linear mixed-effects model (LMM) was used to analyze dynamic changes, and independent t-tests were used to compare baseline differences. RESULTS: In FSCZ patients, W, BMI, WC, ASF, BF, and BFP increased significantly over time (P < 0.05). The olanzapine group (Group A) showed the steepest slopes for W (1.85 kg/4 weeks), BMI (0.70 kg/m²/4 weeks), and WC (3.07 cm/4 weeks) (P < 0.01), indicating central obesity. In CSCZ patients, no significant changes in body composition were observed (P ≥ 0.08), but baseline values of W, BMI, and WC were higher than those of FSCZ patients (P < 0.05). A LMM predicted that FSCZ patients would reach CSCZ levels in W, BMI, and WC in approximately 64, 42, and 28 weeks, respectively, with other indices reaching similar levels within 22.2-67.7 weeks. CONCLUSION: In this preliminary longitudinal study, AAPDs - particularly olanzapine - were associated with rapid and significant increases in central obesity among FSCZ patients. whereas CSCZ patients exhibited metabolic stability over the short observation period. These findings suggest that both disease stage and treatment phase play critical roles in shaping body fat distribution trajectories. The early phase of antipsychotic treatment may represent a vulnerable period for targeted metabolic monitoring and timely intervention to prevent long-term cardiometabolic risks. While these results provide preliminary evidence for stage-specific metabolic patterns, confirmation in larger, randomized, and longer-term studies is required.