What could happen when changing from an antipsychotic to a stimulant?

Case no. 1 (Hollis and Thompson, 2007): A 7-year-old boy with conduct disorder was being treated with risperidone 1.5 mg per day. When a diagnosis of comorbid ADHD was made, the risperidone was abruptly stopped and 12 hours later, methylphenidate extended-release 36 mg per day was started. Within 8 hours of the first dose of methylphenidate,…