A 41-year-old woman is being followed in an outpatient psychiatric clinic for major depressive disorder and comorbid generalized anxiety disorder. She was started on escitalopram 10 mg daily 8 weeks ago. At today's visit, her PHQ-9 score is 8 (down from 17 at baseline) and her GAD-7 score is 6 (down from 14 at baseline). She reports feeling better but still has residual low energy, mild worry about work, and occasional difficulty falling asleep. Using measurement-based care principles, what is the most appropriate next step?