Asymmetry loss is local rather than global in adolescent onset schizophrenia

Meta-analyses in adult-onset schizophrenia report loss of normal planum temporale (PT) asymmetry, posited to relate to language and symptoms, but are inconclusive regarding global "cerebral torque". PT asymmetry has been reported unchanged in childhood onset schizophrenia. Here the discrepancy is examined in adolescence. Unbiased PT asymmetry and torque measures were obtained on 35 adolescents with schizophrenia or schizoaffective disorder and 31 adolescent controls. Patients had less PT asymmetry than controls, but torque was unchanged. Taken with previous reports, these results in adolescent onset psychosis suggest that local disturbance of cerebral asymmetry increases with patient age; it could indicate that differential rate of change at the cortical surface in the two hemispheres is the mechanism of symptom generation.