A 47-year-old female has been in remission from major depressive disorder for the past two years on sertraline 150 mg daily. This was her third lifetime depressive episode. Her first episode occurred at age 26 following a significant interpersonal loss, her second at age 38 during perimenopause, and the most recent episode at age 45 presented with melancholic features including profound psychomotor retardation, early morning awakening, and 15-pound weight loss. Each episode was severe, with the second and third requiring psychiatric hospitalization. She has no residual depressive symptoms, a PHQ-9 score of 2, and reports functioning well in all domains. She asks whether she can discontinue sertraline, stating she feels she no longer needs medication. The PMHNP evaluates whether long-term continuation or discontinuation is indicated. Which evaluation conclusion is most accurate?