title: Bullying and victimisation are common in four-year-old children and are associated with somatic symptoms and conduct and peer problems.
abstract: OBJECTIVE
  There are few population-based studies on bullying behaviour among preschool children. The aims of the study were to investigate the prevalence of bullying behaviour among four-year-old children, as reported by their parents, the prevalence of types of bullying behaviour and the associations between bullying behaviour and psychosocial factors.
  
  
  METHODS
  This study was based on a population-based study sample of 931 children who attended their check-up at a child health clinic at four years of age. Parents completed the questionnaire about their child's bullying behaviour and risk factors during the check-up.
  
  
  RESULTS
  Bullying behaviour, especially being both a bully and a victim, was a common phenomenon among four-year-old children. Being a bully or both a bully and victim were most strongly associated with conduct problems, while being a victim was associated with somatic symptoms and peer problems.
  
  
  CONCLUSIONS
  Bullying behaviour was frequently found in preschool children and associated with a wide range of other problems, which indicate that routine checking of bullying behaviour should be included in child health clinic check-ups. Bullying prevention programmes are usually targeted at school-aged children, but this study highlights the importance of focusing already on preschool children.
authors.affiliation: Department of Child Psychiatry, Faculty of Medicine, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Anna-Marja
authors.initials: AM
authors.lastname: Ilola
authors.affiliation: Department of Child Psychiatry, Faculty of Medicine, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Lotta
authors.initials: L
authors.lastname: Lempinen
authors.affiliation: Department of Child Psychiatry, Faculty of Medicine, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Huttunen
authors.affiliation: Department of Child Psychiatry, Faculty of Medicine, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Terja
authors.initials: T
authors.lastname: Ristkari
authors.affiliation: Department of Child Psychiatry, Faculty of Medicine, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Andre
authors.initials: A
authors.lastname: Sourander
mesh_terms: D058445:Bullying / Q000502:physiology* / Q000706:statistics & numerical data*; D002675:Child, Preschool; D019955:Conduct Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D019548:Crime Victims / Q000523:psychology* / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D007398:Interpersonal Relations; D016015:Logistic Models; D008297:Male; D000071896:Medically Unexplained Symptoms; D010379:Peer Group; D015995:Prevalence; D012307:Risk Factors
keywords: Bullying; Preschool; Psychiatric problems; Victimisation