CYP2C19 and schizophrenia: Multiple regression analysis including CYP2C19 polymorphisms, age, gender, BMI values, smoke and duration of schizophrenia revealed that the polymorphisms of CYP2C19 (standardized beta = 12.480, P < 0.01) and the BMI values (standardized beta = − 1.518, P < 0.05) were correlated with C/D ratios of valproic acid (Table 4).