title: Clinicopathological significance of psychotic experiences in non-psychotic young people: evidence from four population-based studies.
abstract: BACKGROUND
  Epidemiological research has shown that hallucinations and delusions, the classic symptoms of psychosis, are far more prevalent in the population than actual psychotic disorder. These symptoms are especially prevalent in childhood and adolescence. Longitudinal research has demonstrated that psychotic symptoms in adolescence increase the risk of psychotic disorder in adulthood. There has been a lack of research, however, on the immediate clinicopathological significance of psychotic symptoms in adolescence.
  
  
  OBJECTIVE
  To investigate the relationship between psychotic symptoms and non-psychotic psychopathology in community samples of adolescents in terms of prevalence, co-occurring disorders, comorbid (multiple) psychopathology and variation across early v. middle adolescence.
  
  
  METHODS
  Data from four population studies were used: two early adolescence studies (ages 11-13 years) and two mid-adolescence studies (ages 13-16 years). Studies 1 and 2 involved school-based surveys of 2243 children aged 11-16 years for psychotic symptoms and for emotional and behavioural symptoms of psychopathology. Studies 3 and 4 involved in-depth diagnostic interview assessments of psychotic symptoms and lifetime psychiatric disorders in community samples of 423 children aged 11-15 years.
  
  
  RESULTS
  Younger adolescents had a higher prevalence (21-23%) of psychotic symptoms than older adolescents (7%). In both age groups the majority of adolescents who reported psychotic symptoms had at least one diagnosable non-psychotic psychiatric disorder, although associations with psychopathology increased with age: nearly 80% of the mid-adolescence sample who reported psychotic symptoms had at least one diagnosis, compared with 57% of the early adolescence sample. Adolescents who reported psychotic symptoms were at particularly high risk of having multiple co-occurring diagnoses.
  
  
  CONCLUSIONS
  Psychotic symptoms are important risk markers for a wide range of non-psychotic psychopathological disorders, in particular for severe psychopathology characterised by multiple co-occurring diagnoses. These symptoms should be carefully assessed in all patients.
authors.affiliation: Department of Psychiatry, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Ian
authors.initials: I
authors.lastname: Kelleher
authors.forename: Helen
authors.initials: H
authors.lastname: Keeley
authors.forename: Paul
authors.initials: P
authors.lastname: Corcoran
authors.forename: Fionnuala
authors.initials: F
authors.lastname: Lynch
authors.forename: Carol
authors.initials: C
authors.lastname: Fitzpatrick
authors.forename: Nina
authors.initials: N
authors.lastname: Devlin
authors.forename: Charlene
authors.initials: C
authors.lastname: Molloy
authors.forename: Sarah
authors.initials: S
authors.lastname: Roddy
authors.forename: Mary C
authors.initials: MC
authors.lastname: Clarke
authors.forename: Michelle
authors.initials: M
authors.lastname: Harley
authors.forename: Louise
authors.initials: L
authors.lastname: Arseneault
authors.forename: Camilla
authors.initials: C
authors.lastname: Wasserman
authors.forename: Vladimir
authors.initials: V
authors.lastname: Carli
authors.forename: Marco
authors.initials: M
authors.lastname: Sarchiapone
authors.forename: Christina
authors.initials: C
authors.lastname: Hoven
authors.forename: Danuta
authors.initials: D
authors.lastname: Wasserman
authors.forename: Mary
authors.initials: M
authors.lastname: Cannon
mesh_terms: D000293:Adolescent; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000453:epidemiology / Q000523:psychology; D002648:Child; D003702:Delusions / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006212:Hallucinations / Q000453:epidemiology* / Q000523:psychology; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D011618:Psychotic Disorders / Q000453:epidemiology* / Q000523:psychology; D012307:Risk Factors; D013315:Stress, Psychological / Q000453:epidemiology / Q000523:psychology