A 32-year-old man with generalized anxiety disorder is started on escitalopram 10 mg daily. After 8 weeks, he reports minimal improvement despite good adherence. Pharmacogenomic testing reveals he is a CYP2C19 ultrarapid metabolizer. The PMHNP reviews CPIC guidelines to determine how this result should inform her prescribing decision. Which of the following best describes the clinical significance of CYP2C19 ultrarapid metabolizer status for escitalopram therapy?