A PMHNP in an outpatient clinic evaluates a 28-year-old patient presenting with severe obsessive-compulsive disorder that has been refractory to two adequate SSRI trials and clomipramine. The patient reports spending 6 hours daily on rituals and has become unable to work. She has never received exposure and response prevention (ERP) therapy. The patient asks the PMHNP to try another medication combination. The PMHNP considers the most clinically appropriate next step.