A 35-year-old male with schizophrenia has failed sequential trials of risperidone (6 mg/day for 8 weeks) and olanzapine (20 mg/day for 10 weeks) with persistent positive and negative symptoms. He also reports multiple suicide attempts in the past year. The antipsychotic marked **D** in the diagram is now being considered. Which of the following is the PRIMARY reason this agent is preferred in this clinical scenario, despite its significant toxicity profile?