Cerebral glucose metabolism in childhood onset schizophrenia

Abstract

Decreased frontal cortical glucose metabolism has been demonstrated in adult schizophrenics both at rest and while engaging in tasks that normally increase frontal metabolism, such as the Continuous Performance Test (CPT). The authors tested the hypothesis that adolescents with childhood onset schizophrenia would also demonstrate hypofrontality while performing the CPT. Cerebral glucose metabolism was examined in 16 adolescents (mean age 14.1 ± 1.7) with onset of schizophrenia by age 12 (mean age at onset 9.9 ± 1.8) and 26 healthy adolescents selected to be similar in age, sex and handedness using positron emission tomography and 18F-fluorodeoxyglucose. Patients with childhood onset schizophrenia made fewer correct and more incorrect identifications on the CPT. Region of interest analysis revealed no significant group differences in global cerebral metabolism, but increased metabolic rate in supramarginal gyrus ( F = 6.74, P<0.05) and inferior frontal gyrus.insula ( F=7.09, P<0.05) and decreased metabolic rate in middle frontal gyrus ( F=6.72, P<0.05) and superior frontal gyrus ( t=2.04, P<0.05) in schizophrenics. Comparison of effect sizes with an identically designed study of adult schizophrenics did not indicate more severe hypofrontality in childhood onset schizophrenia. Pixel-based analyses indicated a more complex pattern of group differences in cerebral metabolism with bilaterally increased cerebellar metabolic rate in childhood onset schizophrenics. These findings suggest that childhood onset schizophrenia may be associated with a similar, but not more severe, degree of hypofrontality relative to that seen in adult onset schizophrenia.