title: Hearing and speech impairment at age 4 and risk of later non-affective psychosis.
abstract: BACKGROUND
  Schizophrenia often becomes manifest in late adolescence and young adulthood but deviations in physical and behavioural development may already be present in childhood. We investigated the relationship between hearing impairment (measured with audiometry) and speech impairment (broadly defined) at age 4 years and adult risk of non-affective psychosis.
  
  
  METHODS
  We performed a population-based, case–control study in Sweden with 105 cases of schizophrenia or other non-affective psychoses and 213 controls matched for sex, date and place of birth. Information on hearing and speech impairment at age 4, along with potential confounding factors, was retrieved from Well Baby Clinic (WBC) records.
  
  
  RESULTS
  Hearing impairment [odds ratio (OR) 6.0, 95% confidence interval (CI) 1.6–23.2] and speech impairment (OR 2.6, 95% CI 1.4–4.9) at age 4 were associated with an increased risk of non-affective psychotic illness. These associations were mutually independent and not explained by parental psychiatric history, occupational class or obstetric complications.
  
  
  CONCLUSIONS
  These results support the hypothesis that psychosis has a developmental aspect with presentation of antecedent markers early in childhood, long before the disease becomes manifest. Our findings add to the growing evidence that early hearing impairment and speech impairment are risk indicators for later non-affective psychosis and possibly represent aetiological clues and potentially modifiable risk factors. Notably, speech impairment and language impairment are both detectable with inexpensive, easily accessible screening.
authors.affiliation: Division of Public Health Epidemiology, Department of Public Health Sciences, Karolinska Institutet Norrbacka, Stockholm, Sweden. annica.fors@sll.se
authors.forename: A
authors.initials: A
authors.lastname: Fors
authors.forename: K M
authors.initials: KM
authors.lastname: Abel
authors.forename: S
authors.initials: S
authors.lastname: Wicks
authors.forename: C
authors.initials: C
authors.lastname: Magnusson
authors.forename: C
authors.initials: C
authors.lastname: Dalman
mesh_terms: D000328:Adult; D001299:Audiometry / Q000379:methods; D015415:Biomarkers; D016022:Case-Control Studies; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D034381:Hearing Loss / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D011618:Psychotic Disorders / Q000453:epidemiology*; D012042:Registries / Q000706:statistics & numerical data*; D012306:Risk; D012559:Schizophrenia / Q000453:epidemiology*; D013064:Speech Disorders / Q000453:epidemiology*; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
chemical_list: D015415:Biomarkers