title: Bullying in elementary school and psychotic experiences at 18 years: a longitudinal, population-based cohort study.
abstract: BACKGROUND
  Victims of bullying are at risk for psychotic experiences in early adolescence. It is unclear if this elevated risk extends into late adolescence. The aim of this study was to test whether bullying perpetration and victimization in elementary school predict psychotic experiences in late adolescence.
  
  
  METHODS
  The current study is based on the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective community-based study. A total of 4720 subjects with bullying perpetration and victimization were repeatedly assessed between the ages of 8 and 11 years by child and mother reports. Suspected or definite psychotic experiences were assessed with the Psychosis-Like Symptoms semi-structured interview at age 18 years.
  
  
  RESULTS
  Controlling for child's gender, intelligence quotient at age 8 years, childhood behavioural and emotional problems, and also depression symptoms and psychotic experiences in early adolescence, victims [child report at 10 years: odds ratio (OR) 2.4, 95% confidence interval (CI) 1.6-3.4; mother report: OR 1.6, 95% CI 1.1-2.3], bully/victims (child report at 10 years: OR 3.1, 95% CI 1.7-5.8; mother: OR 2.9, 95% CI 1.7-5.0) and bullies (child report at 10 years: OR 4.9, 95% CI 1.3-17.7; mother: OR 1.2, 95% CI 0.46-3.1, n.s.) had a higher prevalence of psychotic experiences at age 18 years. Path analysis revealed that the association between peer victimization in childhood and psychotic experiences at age 18 years was only partially mediated by psychotic or depression symptoms in early adolescence.
  
  
  CONCLUSIONS
  Involvement in bullying, whether as victim, bully/victim or bully, may increase the risk of developing psychotic experiences in adolescence. Health professionals should ask routinely during consultations with children about their bullying of and by peers.
authors.affiliation: Department of Psychology and Warwick Medical School, Division of Mental Health and Wellbeing,University of Warwick,Coventry,UK.
authors.forename: D
authors.initials: D
authors.lastname: Wolke
authors.affiliation: Department of Psychology and Warwick Medical School, Division of Mental Health and Wellbeing,University of Warwick,Coventry,UK.
authors.forename: S T
authors.initials: ST
authors.lastname: Lereya
authors.affiliation: MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry,King's College London,London,UK.
authors.forename: H L
authors.initials: HL
authors.lastname: Fisher
authors.affiliation: Mental Health Sciences Unit,University College London,London,UK.
authors.forename: G
authors.initials: G
authors.lastname: Lewis
authors.affiliation: Mental Health Sciences Unit,University College London,London,UK.
authors.forename: S
authors.initials: S
authors.lastname: Zammit
mesh_terms: D000293:Adolescent; D058445:Bullying / Q000706:statistics & numerical data*; D002648:Child; D019548:Crime Victims / Q000706:statistics & numerical data*; D004739:England; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011618:Psychotic Disorders / Q000453:epidemiology* / Q000209:etiology; D012306:Risk