A 41-year-old woman with schizophrenia has been under psychiatric care for 12 years. Chart review confirms adequate trials of risperidone 6 mg daily for 12 weeks, aripiprazole 30 mg daily for 10 weeks, and olanzapine 20 mg daily for 14 weeks, each with documented adherence via pharmacy refill records and plasma level monitoring where available. Despite these trials, she continues to experience persistent auditory hallucinations, paranoid delusions, and a PANSS positive subscale score of 28. She has no history of substance use disorder, her metabolic panel is within normal limits, and her BMI is 26. The PMHNP is planning the next treatment step. Which treatment plan is most consistent with current evidence-based guidelines?