Limitations
depression, anxiety
A limitation of this study is the observational nature of this substudy, with no manipulation of the variables related to use, which makes it impossible to establish causal relationships between use metrics and outcomes. Moreover, using routine continuous outcome data compared with regular time point assignments comes with challenges, such as many missing questionnaires or complex data processing required to retrieve the relevant assignments. The small size of some of the classes presents another limitation, and future studies may benefit from larger sample sizes that could allow the detection of smaller effects and could provide an opportunity to apply other methods (eg, growth mixture modeling) to allow for both between- and within-class variability. Another limitation was the lack of access to baseline clinical information, which could have been useful for investigating differences between classes. For instance, variables that have been previously linked to treatment response include previous episodes of depression and anxiety [