title: Evaluation of the validity and utility of a transdiagnostic psychosis dimension encompassing schizophrenia and bipolar disorder.
abstract: In recent years, the Kraepelinian dichotomy has been challenged in light of evidence on shared genetic and environmental factors for schizophrenia and bipolar disorder, but empirical efforts to identify a transdiagnostic phenotype of psychosis remain remarkably limited.
  
  
  
  To investigate whether schizophrenia spectrum and bipolar disorder lie on a transdiagnostic spectrum with overlapping non-affective and affective psychotic symptoms.
  
  
  
  Multidimensional item-response modelling was conducted on symptom ratings of the OPerational CRITeria (OPCRIT) system in 1168 patients with schizophrenia spectrum and bipolar disorder.
  
  
  
  A bifactor model with one general, transdiagnostic psychosis dimension underlying affective and non-affective psychotic symptoms and five specific dimensions of positive, negative, disorganised, manic and depressive symptoms provided the best model fit and diagnostic utility for categorical classification.
  
  
  
  Our findings provide support for including dimensional approaches into classification systems and a directly measurable clinical phenotype for cross-disorder investigations into shared genetic and environmental factors of psychosis.
authors.affiliation: Ulrich Reininghaus, PhD, Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK and Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, The Netherlands; Jan R. Böhnke, PhD, Hull York Medical School & Department of Health Sciences, University of York, UK; Georgina Hosang, PhD, Department of Psychology, Goldsmiths, University of London, London, UK; Anne Farmer, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Tom Burns, FRCPsych, Department of Psychiatry, University of Oxford, Oxford, UK; Peter McGuffin, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Richard P. Bentall, PhD, University of Liverpool, Institute of Psychology, Health & Society, Liverpool, UK u.reininghaus@maastrichtuniversity.nl.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Reininghaus
authors.affiliation: Ulrich Reininghaus, PhD, Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK and Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, The Netherlands; Jan R. Böhnke, PhD, Hull York Medical School & Department of Health Sciences, University of York, UK; Georgina Hosang, PhD, Department of Psychology, Goldsmiths, University of London, London, UK; Anne Farmer, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Tom Burns, FRCPsych, Department of Psychiatry, University of Oxford, Oxford, UK; Peter McGuffin, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Richard P. Bentall, PhD, University of Liverpool, Institute of Psychology, Health & Society, Liverpool, UK.
authors.forename: Jan R
authors.initials: JR
authors.lastname: Böhnke
authors.affiliation: Ulrich Reininghaus, PhD, Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK and Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, The Netherlands; Jan R. Böhnke, PhD, Hull York Medical School & Department of Health Sciences, University of York, UK; Georgina Hosang, PhD, Department of Psychology, Goldsmiths, University of London, London, UK; Anne Farmer, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Tom Burns, FRCPsych, Department of Psychiatry, University of Oxford, Oxford, UK; Peter McGuffin, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Richard P. Bentall, PhD, University of Liverpool, Institute of Psychology, Health & Society, Liverpool, UK.
authors.forename: Georgina
authors.initials: G
authors.lastname: Hosang
authors.affiliation: Ulrich Reininghaus, PhD, Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK and Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, The Netherlands; Jan R. Böhnke, PhD, Hull York Medical School & Department of Health Sciences, University of York, UK; Georgina Hosang, PhD, Department of Psychology, Goldsmiths, University of London, London, UK; Anne Farmer, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Tom Burns, FRCPsych, Department of Psychiatry, University of Oxford, Oxford, UK; Peter McGuffin, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Richard P. Bentall, PhD, University of Liverpool, Institute of Psychology, Health & Society, Liverpool, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Farmer
authors.affiliation: Ulrich Reininghaus, PhD, Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK and Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, The Netherlands; Jan R. Böhnke, PhD, Hull York Medical School & Department of Health Sciences, University of York, UK; Georgina Hosang, PhD, Department of Psychology, Goldsmiths, University of London, London, UK; Anne Farmer, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Tom Burns, FRCPsych, Department of Psychiatry, University of Oxford, Oxford, UK; Peter McGuffin, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Richard P. Bentall, PhD, University of Liverpool, Institute of Psychology, Health & Society, Liverpool, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Burns
authors.affiliation: Ulrich Reininghaus, PhD, Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK and Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, The Netherlands; Jan R. Böhnke, PhD, Hull York Medical School & Department of Health Sciences, University of York, UK; Georgina Hosang, PhD, Department of Psychology, Goldsmiths, University of London, London, UK; Anne Farmer, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Tom Burns, FRCPsych, Department of Psychiatry, University of Oxford, Oxford, UK; Peter McGuffin, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Richard P. Bentall, PhD, University of Liverpool, Institute of Psychology, Health & Society, Liverpool, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: McGuffin
authors.affiliation: Ulrich Reininghaus, PhD, Centre for Epidemiology and Public Health, Health Service and Population Research Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK and Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, The Netherlands; Jan R. Böhnke, PhD, Hull York Medical School & Department of Health Sciences, University of York, UK; Georgina Hosang, PhD, Department of Psychology, Goldsmiths, University of London, London, UK; Anne Farmer, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Tom Burns, FRCPsych, Department of Psychiatry, University of Oxford, Oxford, UK; Peter McGuffin, FRCPsych, Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Richard P. Bentall, PhD, University of Liverpool, Institute of Psychology, Health & Society, Liverpool, UK.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Bentall
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000145:classification*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011618:Psychotic Disorders / Q000145:classification*; D012559:Schizophrenia / Q000145:classification*