title: Voxel-based morphometry for separation of schizophrenia from other types of psychosis in first episode psychosis.
abstract: BACKGROUND
  Schizophrenia is a psychiatric disorder which involves distortions in thought and perception, blunted affect, and behavioural disturbances. The longer psychosis goes unnoticed and untreated, the more severe the repercussions for relapse and recovery. There is some evidence that early intervention services can help, and diagnostic techniques that could contribute to early intervention may offer clinical utility in these situations. The index test being evaluated in this review is the structural magnetic resonance imaging (MRI) analysis technique known as voxel-based morphometry (VBM) that estimates the distribution of grey matter tissue volume across several brain regions. This review is an exploratory examination of the diagnostic 'potential' of VBM for use as an additional tool in the clinical examination of patients with first episode psychosis to establish whether an individual will progress on to developing schizophrenia as opposed to other types of psychosis.
  
  
  OBJECTIVE
  To determine whether VBM applied to the brain can be used to differentiate schizophrenia from other types of psychosis in participants who have received a clinical diagnosis of first episode psychosis.
  
  
  METHODS
  In December 2013, we updated a previous search (May 2012) of MEDLINE, EMBASE, and PsycInfo using OvidSP.
  
  
  METHODS
  We included retrospective and prospective studies that consecutively or randomly selected adolescent and adult participants (< 45 years) with a first episode of psychosis; and that evaluated the diagnostic accuracy of VBM for differentiating schizophrenia from other psychoses compared with a clinical diagnosis made by a qualified mental health professional, with or without the use of standard operational criteria or symptom checklists. We excluded studies in children, and in adult participants with organic brain disorders or who were at high risk for schizophrenia, such as people with a genetic predisposition.
  
  
  METHODS
  Two review authors screened all references for inclusion. We assessed the quality of studies using the QUADAS-2 instrument. Due to a lack of data, we were not able to extract 2 x 2 data tables for each study nor undertake any meta-analysis.
  
  
  RESULTS
  We included four studies with a total of 275 participants with first episode psychosis. VBM was not used to diagnose schizophrenia in any of the studies, instead VBM was used to quantify the magnitude of differences in grey matter volume. Therefore, none of the included studies reported data that could be used in the analysis, and we summarised the findings narratively for each study.
  
  
  CONCLUSIONS
  There is no evidence to currently support diagnosing schizophrenia (as opposed to other psychotic disorders) using the pattern of brain changes seen in VBM studies in patients with first episode psychosis. VBM has the potential to discriminate between diagnostic categories but the methods to do this reliably are currently in evolution. In addition, the lack of applicability of the use of VBM to clinical practice in the studies to date limits the usefulness of VBM as a diagnostic aid to differentiate schizophrenia from other types of psychotic presentations in people with first episode of psychosis.
authors.affiliation: Divison of Psychiatry, Institute of Mental Health, The University of Nottingham, Room 09, C Floor, Innovation Park, Triumph Road, Nottingham, UK, NG7 2TU.
authors.forename: Lena
authors.initials: L
authors.lastname: Palaniyappan
authors.forename: Nicola
authors.initials: N
authors.lastname: Maayan
authors.forename: Hanna
authors.initials: H
authors.lastname: Bergman
authors.forename: Clare
authors.initials: C
authors.lastname: Davenport
authors.forename: Clive E
authors.initials: CE
authors.lastname: Adams
authors.forename: Karla
authors.initials: K
authors.lastname: Soares-Weiser
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D042241:Early Diagnosis; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011618:Psychotic Disorders / Q000473:pathology*; D012559:Schizophrenia / Q000473:pathology*