title: Reduced dorso-lateral prefrontal cortex in treatment resistant schizophrenia.
abstract: BACKGROUND
  Treatment resistance affects up to one third of patients with schizophrenia (SCZ). A better understanding of its biological underlying processes could improve treatment. The aim of this study was to compare cortical thickness between non-resistant SCZ (NR-SCZ), treatment-resistant SCZ (TR-SCZ) patients and healthy controls (HC).
  
  
  METHODS
  Structural MRI scans were obtained from 3 groups of individuals: 61 treatment resistant SCZ individuals, 67 non-resistant SCZ and 80 healthy controls. Images were analyzed using cortical surface modelling (implemented in freesurfer package) to identify group differences in cortical thickness. Statistical significant differences were identified using Monte-Carlo simulation method with a corrected p-cluster<0.01.
  
  
  RESULTS
  Patients in the TR-SCZ group showed a widespread reduction in cortical thickness in frontal, parietal, temporal and occipital regions bilaterally. NR-SCZ group had reduced cortex in two regions (left superior frontal cortex and left caudal middle frontal cortex). TR-SCZ group also showed decreased thickness in the left dorsolateral prefrontal cortex (DLPFC) when compared with patients from NR-SCZ group.
  
  
  CONCLUSIONS
  The reduction in cortical thickness in DLPFC indicates a more severe form of the disease or a specific finding for this group. Alterations in this region should be explored as a putative marker for treatment resistance. Prospective studies, with individuals being followed from first episode psychosis until refractoriness is diagnosed, are needed to clarify these hypotheses.
authors.affiliation: Interdiciplinary Laboratory in Clinical Neuroscience (LiNC), Department of Psychiatry, Federal University of São Paulo, São Paulo, Brazil. andre.zugman@gmail.com
authors.forename: André
authors.initials: A
authors.lastname: Zugman
authors.forename: Ary
authors.initials: A
authors.lastname: Gadelha
authors.forename: Idaiane
authors.initials: I
authors.lastname: Assunção
authors.forename: João
authors.initials: J
authors.lastname: Sato
authors.forename: Vanessa K
authors.initials: VK
authors.lastname: Ota
authors.forename: Deyvis L
authors.initials: DL
authors.lastname: Rocha
authors.forename: Jair J
authors.initials: JJ
authors.lastname: Mari
authors.forename: Sintia I
authors.initials: SI
authors.lastname: Belangero
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Bressan
authors.forename: Elisa
authors.initials: E
authors.lastname: Brietzke
authors.forename: Andrea P
authors.initials: AP
authors.lastname: Jackowski
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000187:drug effects / Q000473:pathology*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000473:pathology*; D012559:Schizophrenia / Q000188:drug therapy / Q000473:pathology*; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents
keywords: Cortical thickness; MRI; Refractory; Schizophrenia; Treatment resistant