title: White matter metabolism differentiates schizophrenia and bipolar disorder: a preliminary PET study.
abstract: Fluorodeoxyglucose-F18 positron emission tomography studies (FDG-PET) have shown similar corticolimbic metabolic dysregulation in bipolar disorder and schizophrenia, with hypoactive prefrontal cortex coupled with hyperactive anterior limbic areas. However, it is not clear whether white matter metabolism connecting these regions is differently affected in the two disorders. Twenty-six patients with schizophrenia (mean age ± S.D.=30.23 ± 9.7 year-old; 19 males; mean weight ± S.D.=71 ± 3 kg) and 26 patients with bipolar disorder (mean age ± S.D.=48.73 ± 13 year-old; 18 males; mean weight ± S.D.=75 ± 15 kg) underwent an FDG-PET scan. Normalized datasets the two groups of patients were compared on a voxel-by-voxel basis using a two-sample t statistic test as implemented in SPM8, and adding age as covariate. Group differences were assessed applying a threshold of p<0.0005. White matter metabolic rates significantly differed between schizophrenia and bipolar disorder, whereas no differences were shown for cortical activity. This is the first FDG-PET, to our best knowledge, directly comparing subjects with schizophrenia to those with bipolar disorder. It reports decreased activity in the center of large fronto-temporal and cerebellar white matter tracts in patients with schizophrenia in respect to those with bipolar disorder. This feature may characterize and differentiate the regional brain metabolism of the two illnesses.
authors.affiliation: Department of Neurosciences, University of Milan, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Alfredo Carlo
authors.initials: AC
authors.lastname: Altamura
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bertoldo
authors.forename: Giorgio
authors.initials: G
authors.lastname: Marotta
authors.forename: Riccardo Augusto
authors.initials: RA
authors.lastname: Paoli
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Caletti
authors.forename: Filippo
authors.initials: F
authors.lastname: Dragogna
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Buoli
authors.forename: Valentina
authors.initials: V
authors.lastname: Baglivo
authors.forename: Massimo Carlo
authors.initials: MC
authors.lastname: Mauri
authors.forename: Paolo
authors.initials: P
authors.lastname: Brambilla
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000378:metabolism*; D001921:Brain / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000378:metabolism*; D049268:Positron-Emission Tomography; D012559:Schizophrenia / Q000378:metabolism*
chemical_list: D005947:Glucose
keywords: Brain activity; Cerebellum; Connectivity; Limbic structures; Prefrontal cortex