165. An fMRI study of cognitive activation deficits in symptom-matched first episode and chronic schizophrenia patients

Abstract

To determine whether abnormal patterns of cerebral activation previously detected in chronic schizophrenia are also present in the first episode, functional magnetic resonance imaging (fMRI) was used to compare brain function in first episode and chronic schizophrenia during a verbal working memory task. Six male, right-handed first episode schizophrenic patients were matched to chronic patients on PANSS scores. One first episode patient was antipsychotic naive; all others were receiving conventional antipsychotics. There was no significant difference in mean daily dose of chlorpromazine equivalents. Two age-matched control groups were used. There was no significant difference between any of the four groups on estimated premorbid IQ. All subjects underwent fMRI while performing a verbal working memory task (the two-back task) incorporating a periodic design. An analysis of variance (p , .01) on a voxel-wise basis was used to compare the first episode group (controls-patients) and the chronic group (controlspatients). The only significant difference in task performance between the four groups was in reaction time during the two back task: Both patient groups had reaction times slower than their respective controls (p , .05). There was no significant difference in activation pattern between the first episode group (controls-patients) and the chronic group (controls-patients). Abnormal patterns of cerebral activation in first episode schizophrenia are similar to those in chronic schizophrenia. Previously detected abnormalities in chronic schizophrenia cannot therefore be solely ascribed to psychosis symptomatology, long-term exposure to antipsychotics, or to post-onset disease progression.