title: Schizophrenia in the internalizing-externalizing framework: a third dimension?
abstract: BACKGROUND
  Prior studies of common disorders in community-dwelling adults identified internalizing and externalizing spectra of mental illness. We investigated the placement of schizophrenia and schizotypal personality disorder in this framework and tested the validity of the resulting organization in a clinical population.
  
  
  METHODS
  The data came from the Suffolk County Mental Health Project cohort (N = 628), which consists of first-admission patients with psychosis recruited from inpatient units throughout Suffolk County, NY (72% response rate). The sample was reassessed multiple times over the following 10 years. Complete diagnostic data were available for 469 participants. Mental health professionals diagnosed 11 target conditions based on semistructured clinical interviews, review of medical records, and reports of significant others. Two validators were included: family history of schizophrenia and 10-year illness course.
  
  
  RESULTS
  Confirmatory factor analysis revealed that the The Diagnostic and Statistical Manual of Mental Disorders-IV grouping of conditions fit the data poorly. The best alternative classification consisted of three clusters: internalizing, externalizing, and schizophrenic. Both validators supported the coherence and distinctiveness of the schizophrenic cluster.
  
  
  CONCLUSIONS
  We replicated internalizing and externalizing spectra in a clinical population, identified a schizophrenic spectrum, and provided initial evidence of its validity. These findings suggest that schizotypal personality disorder may be better placed with schizophrenia, antisocial conditions with substance use disorders, and major depression with anxiety disorders.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stony Brook University, Stony Brook, NY, USA. roman.kotov@stonybrook.edu
authors.forename: Roman
authors.initials: R
authors.lastname: Kotov
authors.forename: Su-Wei
authors.initials: SW
authors.lastname: Chang
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Fochtmann
authors.forename: Ramin
authors.initials: R
authors.lastname: Mojtabai
authors.forename: Gabrielle A
authors.initials: GA
authors.lastname: Carlson
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sedler
authors.forename: Evelyn J
authors.initials: EJ
authors.lastname: Bromet
mesh_terms: D000293:Adolescent; D000328:Adult; D000987:Antisocial Personality Disorder; D001008:Anxiety Disorders / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000453:epidemiology / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005163:Factor Analysis, Statistical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology; D012565:Schizophrenic Psychology; D012569:Schizotypal Personality Disorder / Q000453:epidemiology / Q000523:psychology*; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000523:psychology; D055815:Young Adult