Moreover, in the graphs for both depression and anxiety (Figure 2), it can be observed that there is substantial variability in use between the PHQ and GAD classes, where most of the variability between classes seems to occur in the early stages of treatment (first 4 weeks), and the differences between classes in the other 2 periods (weeks 4-8 and weeks 8-12) are less obvious. This evidence concerns the gene GAD1 and depressive disorder.