title: Prevalence of mental illness, intellectual disability, and developmental disability among homeless people in Nagoya, Japan: A case series study.
abstract: OBJECTIVE
  While it has been reported that the prevalence of mental illness is higher in homeless people than in the national population, few studies have investigated the prevalence of intellectual and developmental disability among the homeless. In this study, we conducted a survey to comprehensively assess these mental problems among homeless people in Nagoya, Japan.
  
  
  METHODS
  The subjects were 18 homeless men. Mental illness was diagnosed with semi-structured interviews conducted by psychiatrists. We used the Wechsler Adult Intelligence Scale III to diagnose intellectual disability. Discrepancies between Wechsler Adult Intelligence Scale III subtest scores were used as criteria for developmental disability.
  
  
  RESULTS
  Eleven of the 18 participants were diagnosed with mental illness: six with mood disorder, two with psychotic disorder, and six with alcohol problems. The mean IQ of all subjects was 83.4 ± 27.4. The 95% confidence interval (CI) was 96.2-69.1. Seven participants were found to have intellectual disability. Three men showed discrepancies of more than 10 between subtest scores, and all of them were diagnosed with a mental illness. We divided the participants into four groups: those with mental illness only; those with intellectual disability only; those with both problems; and those without diagnosis. The men with intellectual disability only were significantly younger and had been homeless since a younger age than the other groups. Participants diagnosed with a mental illness had been homeless for longer than those without mental health problems.
  
  
  CONCLUSIONS
  Although the sample size was limited, this study revealed the high prevalence of mental illness and intellectual disability, 61% (95%CI, 35-83%) and 39% (95%CI, 17-64%), respectively, in homeless people in Nagoya, Japan.
authors.affiliation: Health Administration Center, Gifu University, Gifu, Japan.|Department of Psychopathology, Division of Neuroscience, Graduate School of Medicine, Gifu University, Gifu, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nishio
authors.affiliation: Health Administration Center, Gifu University, Gifu, Japan.|United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Psychopathology, Division of Neuroscience, Graduate School of Medicine, Gifu University, Gifu, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ueki
authors.affiliation: Midori Hospital, Gifu, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Kanazawa Johoku Hospital, Kanazawa, Japan.
authors.forename: Kenshin
authors.initials: K
authors.lastname: Matsuura
authors.affiliation: Hokkaido Labor Hospital, Sapporo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Tamura
authors.affiliation: Yoshida Hospital, Nara, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Uehara
authors.affiliation: Department of Psychopathology, Division of Neuroscience, Graduate School of Medicine, Gifu University, Gifu, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Shioiri
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D002658:Developmental Disabilities / Q000453:epidemiology*; D006703:Ill-Housed Persons / Q000523:psychology* / Q000706:statistics & numerical data*; D006801:Humans; D008607:Intellectual Disability / Q000453:epidemiology*; D007564:Japan / Q000453:epidemiology; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D008875:Middle Aged; D015995:Prevalence
keywords: Wechsler Adult Intelligence Scale Third Edition; developmental disability; homeless; intellectual disabilities; mental illness