A 20 year old female patient with schizophrenia has been stabilized on an antipsychotic, but is complaining that she is too tired and sleepy to attend her classes at the local community college. She verbalizes, "I want to try something else that does not cause me to be so sleepy during the day." Which of the following options below may be considered to least likely cause sedation.

A. Aripiprazole: Aripiprazole is a partial dopamine D2 agonist with minimal histamine H1 and muscarinic receptor antagonism, which contributes to its low sedative profile. Patients are less likely to experience daytime sleepiness, making it a suitable option for those needing alertness for daily activities. B. Olanzapine: Olanzapine has strong H1 and muscarinic antagonism, which commonly causes significant sedation and daytime sleepiness. Switching to olanzapine would likely worsen fatigue rather than improve it. C. Paliperidone: Paliperidone, an active metabolite of risperidone, has moderate antihistaminic activity. It can cause sedation, particularly at higher doses, and may not resolve the patient’s concern about daytime sleepiness. D. Perphenazine: Perphenazine is a mid-potency first-generation antipsychotic. While less sedating than low-potency agents, it still carries moderate risk for drowsiness and anticholinergic side effects, making it less ideal for patients needing high daytime alertness.