The psychiatric-mental health nurse practitioner is treating a 6-year-old boy with autism spectrum disorder (ASD) who has not responded to 9 months of psychosocial therapy and continues hitting his younger brother. What is the most appropriate treatment for the PMHNP to initiate at this time?

Choice A reason: Sertraline, an SSRI, may help with anxiety or repetitive behaviors but has limited evidence for treating aggression in children with ASD. Choice B reason: Carbamazepine is an anticonvulsant, sometimes used for mood stabilization, but is not first-line for irritability or aggression in ASD. Choice C reason: Risperidone is FDA-approved for irritability, aggression, and self-injurious behavior in children with ASD and is considered first-line pharmacologic treatment for these behaviors. Choice D reason: Venlafaxine, an SNRI, is not indicated for aggression in ASD and lacks evidence for treating behavioral symptoms in this population.