A 34-year-old male with major depressive disorder has been taking sertraline 100 mg daily for 8 weeks with significant improvement in mood. He now reports difficulty achieving orgasm and decreased libido that began approximately 3 weeks after starting the medication. He denies relationship problems, substance use, or other new stressors. His PHQ-9 score has decreased from 22 to 6. He asks the PMHNP about the sexual difficulties. Which assessment finding is most important in determining that the sexual dysfunction is medication-related rather than attributable to another cause?