A 44-year-old woman with major depressive disorder treated with escitalopram 20 mg daily for 10 weeks reports significant improvement in mood and motivation, with her PHQ-9 decreasing from 21 to 8. However, she continues to experience significant insomnia, with a sleep onset latency of 60 to 90 minutes and frequent middle-of-the-night awakenings, resulting in an average of four to five hours of sleep per night. She reports that the insomnia predated her depressive episode by approximately two years and has not improved despite the antidepressant's therapeutic effect on her other symptoms. She denies use of caffeine after noon, maintains a regular wake time, and has adequate sleep hygiene. The PMHNP is developing a treatment plan to address the persistent insomnia. Which of the following approaches is most appropriate?