J Psychiatry Neurosci 2012;37(4):297-30
C. Faget-Agius, L. Boyer, R. Padovani, R. Richieri, O. Mundler, C. Lançon, E. Guedj
Faget-Agius, Boyer, Padovani, Richieri, Lançon — Aix-Marseille University, Research Unit EA 3279, Marseille; Faget-Agius, Padovani, Richieri, Lançon — Hôpital Sainte Marguerite, Département de psychiatrie, Marseille; Boyer — Hôpital de la Timone, Département de santé publique, Marseille; Mundler, Guedj — Hôpital de la Timone, Service Central de Biophysique et Médecine Nucléaire, Aix-Marseille University and European Centre for Research on Medical Imaging (CERIMED), Marseille; Guedj — Aix-Marseille University and the Centre national de la recherche scientifique, Institut de Neurosciences de la Timone (INT), UMR CNRS 7289, Marseille, France
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.
Limitations: 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.
Conclusion: 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 frontotemporal impairment.
Submitted Sept. 14, 2011; Revised Jan. 2, Feb. 10, 2012; Accepted Feb. 10, 2012.
Acknowledgements: This work was supported by the Institut national de la santé et de la recherche médicale (INSERM; Centre d’Investigation Clinique, Hôpital de la Conception, Marseille) and by Assistance Publique — Hôpitaux de Marseille (AP-HM; PHRC 2007/09).
Competing interests: None declared.
Contributors: C. Faget-Agius, R. Richieri, O. Mundler, C. Lançon and E. Guedj designed the study. C. Faget-Agius, R. Padovani, R. Richieri, O. Mundler and E. Guedj acquired the data. L. Boyer and E. Guedj analyzed the data. C. Faget-Agius, L. Boyer and E. Guedj wrote the article. C. Faget-Agius, R. Padovani, R. Richieri, O.Mundler, C. Lançon and E. Guedj reviewed the article. All authors approved its publication.
Correspondence to: E. Guedj, Service Central de Biophysique et de Médecine Nucléaire, Hôpital de la Timone, 264, rue Saint Pierre, 13385 Marseille Cedex 5, France; email@example.com