Amphetamine challenge test, response to treatment, and lateral ventricle size in schizophrenia

The hypothesis of two independent pathologies in schizophrenia proposed by Crow (1980) were tested. Two dimensions of the dopamine variable, namely, the behavioral response during the Amphetamine Challenge Test (ACT) and the response to neuroleptic treatment, were studied in a cohort of 19 subjects with a research diagnosis of schizophrenia (n = 18) or schizoaffective disorder (n = 1) in an acute inpatient setting. The size of the lateral ventricle was assessed by mesauring the ventricle-brain ratio (VBR) on the computerized tomographic brain scan. Patients who had greater symptom reduction with the neuroleptic treatment worsened more in their positive psychotic symptoms during the ACT. Those with larger VBRs showed less treatment responsiveness and no worsening during the ACT. The findings are supportive of Crow's hypothesis. The ACT has the potential to be an index of both Type I and Type II pathologies.