Behavioral response to methylphenidate and treatment outcome in first episode schizophrenia.

In order to examine the relationship of behavioral response to psychostimulants and acute treatment response, we administered methylphenidate (0.5 mg/kg i.v.), an indirect dopamine (DA) agonist, to 38 patients who met Research Diagnostic Criteria (RDC) for definite or probable schizophrenia or schizoaffective disorder, were experiencing their first acute episode of psychosis, and had received less than 12 weeks or no prior lifetime neuroleptic exposure. Following baseline methylphenidate infusions, patients received a standardized regimen of acute neuroleptic treatment. Methylphenidate produced an increase in psychopathology reflected by a worsening of both positive and negative symptoms. Using a priori criteria, 61 percent of patients exhibited psychotic symptom activation, and 39 percent showed no change. Activation during methylphenidate infusion during the initial acute phase of illness was not correlated with time to achieve antipsychotic treatment response but was associated with side-effect vulnerability.