A 21-year-old male was diagnosed with schizophrenia after a recent hospitalization. He has a family history of schizophrenia in his older brother who experienced symptoms at a similar age. The patient is a heavy cannabis user, smoking up to 10g daily. While on the inpatient ward, you are discussing cannabis cessation and the need for an antipsychotic agent. The patient is determined to get well and is amenable to any changes you recommend. However, he voices concerns about weight gain with antipsychotic medication since his brother gained 50lbs in his first year on treatment. The patient is a football player and hopes to play professionally. Any weight gain would ruin his chances of being recruited by a professional team. Which of the following is best suited for this patient?