title: Is late-onset schizophrenia a subtype of schizophrenia?
abstract: OBJECTIVE
  To determine whether late-onset schizophrenia (LOS, onset after age 40) should be considered a distinct subtype of schizophrenia.
  
  
  METHODS
  Participants included 359 normal comparison subjects (NCs) and 854 schizophrenia out-patients age >40 (110 LOS, 744 early-onset schizophrenia or EOS). Assessments included standardized measures of psychopathology, neurocognition, and functioning.
  
  
  RESULTS
  Early-onset schizophrenia and LOS groups differed from NCs on all measures of psychopathology and functioning, and most cognitive tests. Early-onset schizophrenia and LOS groups had similar education, severity of depressive, negative, and deficit symptoms, crystallized knowledge, and auditory working memory, but LOS patients included more women and married individuals, had less severe positive symptoms and general psychopathology, and better processing speed, abstraction, verbal memory, and everyday functioning, and were on lower antipsychotic doses. Most EOS-LOS differences remained significant after adjusting for age, gender, severity of negative or deficit symptoms, and duration of illness.
  
  
  CONCLUSIONS
  Late-onset schizophrenia should be considered a subtype of schizophrenia.
authors.affiliation: Sam and Rose Stein Institute for Research on Aging, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: I V
authors.initials: IV
authors.lastname: Vahia
authors.forename: B W
authors.initials: BW
authors.lastname: Palmer
authors.forename: C
authors.initials: C
authors.lastname: Depp
authors.forename: I
authors.initials: I
authors.lastname: Fellows
authors.forename: S
authors.initials: S
authors.lastname: Golshan
authors.forename: H C
authors.initials: HC
authors.lastname: Kraemer
authors.forename: Dilip V
authors.initials: DV
authors.lastname: Jeste
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003071:Cognition; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000145:classification* / Q000175:diagnosis / Q000453:epidemiology; D012565:Schizophrenic Psychology; D012737:Sex Factors