A 31-year-old male, diagnosed with schizophrenia and receiving maintenance treatment with olanzapine, was prescribed methylphenidate for comorbid attention deficit hyperactivity disorder (adhd). The adhd symptoms diminished and there were hardly any side-effects. No increase in psychotic symptoms occurred. The patient used far fewer amphetamines and benzodiazepines. In theory, stimulants and antipsychotics produce opposite effects. Relevant literature on the subject is discussed.