FIGURE 1.

The daily dose–metabolite/parent substance ratios for aripiprazole, clozapine, and risperidone correlation were analyzed by linear regression (regression lines with 95% confidence intervals). Two extreme ratios (3.71 and 1.52, respectively) were excluded from the dehydroaripiprazole/aripiprazole figure, one ratio (36.5) was excluded from the desmethylclozapine/clozapine figure, and one ratio (300) was excluded from the 9-hydroxyrisperidone/risperidone figure. The slopes of the regression lines were significantly different from zero (r² = 0.007; P = 0.0008 for dehydroaripiprazole/aripiprazole; r² = 0.01 P < 0.0001 for desmethylclozapine/clozapine; r² = 0.01; P < 0.0001 for 9-hydroxyrisperidone/risperidone).