title: Schizophrenia spectrum disorders in later life:  prevalence and distribution of age at onset and sex in a dutch catchment area.
abstract: OBJECTIVE
  The prevalence of schizophrenia in later life is affected by both outflow of early onset patients, due to recovery and excess mortality, and inflow of patients with a later age at onset, making it likely that characteristics of older patients differ markedly from younger patients. We assessed the prevalence of schizophrenia and spectrum disorders and their distribution according to age at onset and sex in an elderly population.
  
  
  METHODS
  Case register study.
  
  
  METHODS
  All patients age 60 years and older, in contact with the Mental Health Organization in a psychiatric catchment area in Amsterdam (the Netherlands), diagnosed with schizophrenia, schizoaffective disorder, or delusional disorder.
  
  
  METHODS
  One-year prevalence estimates, including rates according to age group, age at onset, and sex. In addition, we determined the effect of using different criteria for age at onset.
  
  
  RESULTS
  The one-year prevalence of all disorders was 0.71%, subdivided in 0.55% for schizophrenia, 0.14% for schizoaffective disorder, and 0.03% for delusional disorder. The one-year prevalence of early-onset schizophrenia was 0.35%, of late-onset schizophrenia 0.14%, and of very-late-onset schizophrenia-like psychosis 0.05%. Variation of onset criterion affected the proportion of early-onset versus late-onset schizophrenia patients stronger in women than in men. Women outnumbered men markedly in the prevalence estimates for most diagnostic subgroups, including early-onset schizophrenia.
  
  
  CONCLUSIONS
  We found the prevalence of schizophrenia among older persons to be well within the range reported for younger populations. The considerable proportion with a later age at onset and the strong female preponderance are distinguishing characteristics of older patients with clinical implications.
authors.affiliation: GGZ inGeest, VU University Medical Center, Amsterdam, the Netherlands. p.meesters@ggzingeest.nl
authors.forename: Paul D
authors.initials: PD
authors.lastname: Meesters
authors.forename: Lieuwe
authors.initials: L
authors.lastname: de Haan
authors.forename: Hannie C
authors.initials: HC
authors.lastname: Comijs
authors.forename: Max L
authors.initials: ML
authors.lastname: Stek
authors.forename: Maureen M J
authors.initials: MM
authors.lastname: Smeets-Janssen
authors.forename: Marjan R
authors.initials: MR
authors.lastname: Weeda
authors.forename: Piet
authors.initials: P
authors.lastname: Eikelenboom
authors.forename: Johannes H
authors.initials: JH
authors.lastname: Smit
authors.forename: Aartjan T F
authors.initials: AT
authors.lastname: Beekman
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D002391:Catchment Area, Health / Q000706:statistics & numerical data*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D011618:Psychotic Disorders / Q000453:epidemiology*; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D012563:Schizophrenia, Paranoid / Q000453:epidemiology*; D012737:Sex Factors