Body mass index-specific metabolic profiles in schizophrenia: implications for cognitive dysfunction and psychopathology.

While metabolic dysfunction is linked to schizophrenia, the relationship between metabolic parameters, cognitive function, and psychopathological symptoms across different body mass index (BMI) categories remains inadequately understood. This study aimed to explore the distinct metabolic predictors of cognitive and psychopathological outcomes in schizophrenia patients stratified by BMI. A total of 1034 patients with schizophrenia were recruited and categorized into underweight, normal weight, overweight and obesity groups. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status, and psychopathological symptoms were evaluated using the Positive and Negative Syndrome Scale. Metabolic profiles and anthropometric measures were obtained via standard tests. Significant metabolic differences were found across BMI groups, except for low-density lipoprotein. Underweight patients performed worse in language compared to obese patients, which had higher positive symptom but lower negative symptom scores. Multivariate linear regression analysis revealed that in obese patients, elevated triglyceride was independently associated with better cognitive performance (p < 0.05). In overweight patients, waist-hip ratio was significantly correlated with cognitive outcomes, which specifically predicting the severity of positive symptoms (all p < 0.05). In underweight patients, fasting blood glucose (β = 0.77, p < 0.05) and triglyceride (β = 1.28, p < 0.01) were associated with immediate memory deficits, while attention was negatively influenced by high-density lipoprotein levels (β = -0.10, p < 0.05). Schizophrenia patients exhibit distinct BMI-specific metabolic patterns that differentially predict cognitive and psychopathological outcomes, highlighting the importance of tailored metabolic interventions based on BMI stratification.