title: Schizophrenia with preserved insight is associated with increased perfusion of the precuneus.
abstract: BACKGROUND
  Preserved insight into illness has been suggested to be predictive of outcome in patients with schizophrenia. We aimed to investigate the functional substrate underlying preserved insight in these patients.
  
  
  METHODS
  We recruited patients with paranoid schizophrenia and healthy controls matched for age and sex. Patients were grouped according to preserved or impaired insight into illness using the Scale to assess Unawareness of Mental Disorder (SUMD). Whole-brain technetium-99m ethyl cysteinate dimer single photon emission computed tomography regional cerebral blood flow was compared at the voxel level between the 2 groups using a statistical parametric map (voxel-level significance of p < 0.001, uncorrected; cluster level significance of p < 0.05, uncorrected).
  
  
  RESULTS
  We enrolled 31 right-handed patients with schizophrenia and 18 controls in our study. Twenty-one (67.7%) patients had preserved insight. The 2 groups did not differ significantly in demographic and clinical characteristics or in treatment. Compared with controls, the whole group of patients showed bilateral frontotemporal hypoperfusions, with no statistical difference between patients with preserved or impaired insight for these areas. Patients with preserved insight showed significantly increased perfusion of the bilateral precuneus relative to those with impaired insight.
  
  
  CONCLUSIONS
  Patients with subtypes other than paranoid schizophrenia have to be investigated to assess whether involvement of the precuneus in patients with preserved insight can be identified across the full spectrum of subtypes and symptoms of schizophrenia. Moreover, our study concerned only the central dimension (awareness of mental disorder) of 1 scale (SUMD); other dimensions of insight could be studied.
  
  
  CONCLUSIONS
  Our results show that schizophrenia with preserved insight is associated with greater perfusion of the precuneus, a brain area known to be involved in self- consciousness, suggesting a compensatory mechanism of fronto-temporal impairment.
authors.affiliation: Aix-Marseille University, Research Unit EA 3279, Marseille; Hôpital Sainte Marguerite, Département de psychiatrie, Marseille, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Faget-Agius
authors.forename: Laurent
authors.initials: L
authors.lastname: Boyer
authors.forename: Romain
authors.initials: R
authors.lastname: Padovani
authors.forename: Raphaëlle
authors.initials: R
authors.lastname: Richieri
authors.forename: Olivier
authors.initials: O
authors.lastname: Mundler
authors.forename: Christophe
authors.initials: C
authors.lastname: Lançon
authors.forename: Eric
authors.initials: E
authors.lastname: Guedj
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000098:blood supply; D003553:Cystine / Q000031:analogs & derivatives; D005260:Female; D059907:Functional Neuroimaging / Q000379:methods / Q000523:psychology*; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000098:blood supply* / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012559:Schizophrenia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D012647:Self-Assessment; D013667:Technetium; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods / Q000523:psychology
chemical_list: D019275:Radiopharmaceuticals; C541351:ethyl cysteinate dimer; D003553:Cystine; D013667:Technetium