Reversed cerebellar asymmetry in men with first-episode schizophrenia.

Background: Abnormalities in cerebellar structure and function have been implicated in the pathophysiology of schizophrenia. In this study, we investigated whether patients experiencing first-episode schizophrenia differed from healthy comparison subjects in regional cerebellar volumes or cerebellar asymmetry.
Methods: Volumes of four cerebellar regions (right, left; anterior, posterior) were measured from contiguous coronal magnetic resonance (MR) images in 69 (37 men, 32 women) patients experiencing first-episode schizophrenia and in 49 (27 men, 22 women) healthy comparison subjects. Patients were rated on the Scale for the Assessment of Negative Symptoms and the Schedule for Affective Disorders and Schizophrenia-Psychosis/Disorganization before the initiation of antipsychotic medication and at the time of the MR imaging exam.
Results: Patients and healthy comparison subjects did not differ in regional cerebellar volumes, but male patients demonstrated significantly reversed anterior and posterior asymmetry compared with healthy male subjects. Among male patients, greater reversals in a composite measure of cerebellar asymmetry (i.e., torque) correlated significantly with increased negative symptoms before the initiation of antipsychotic medication.
Conclusions: These findings implicate an aberrant neurodevelopmental process involving the metencephalon in the pathophysiology of schizophrenia and are consistent with prior studies implicating abnormal asymmetry in schizophrenia at the neocortical level.