title: Direct and indirect aggression and victimization in adolescents - associations with the development of psychological difficulties.
abstract: BACKGROUND
  Previous research has established that direct and indirect forms of aggression differ in their association with gender and type of psychological difficulties. One purpose of the present study was to test if the same applies to direct and indirect victimization. A second purpose was to study these associations not only cross-sectionally (as in most previous research) but also longitudinally. A third purpose was to test the hypotheses that there are prospective bidirectional associations not only between victimization and psychological difficulties (which has been shown in previous research), but also between aggression and psychological difficulties, and that direct and indirect forms of aggression and victimization show different associations with different types of psychological difficulties.
  
  
  METHODS
  The participants were a community sample of all students in two grades of regular school in a Swedish municipality who answered questionnaires as part of a two-wave longitudinal study with a one-year interval. The participants were 13-15 years old, and there were longitudinal data on 893 students, which represented 85% of all students. The cross-sectional associations were primarily tested by semi-partial correlations, and the longitudinal associations by hierarchical multiple regression.
  
  
  RESULTS
  The results corroborated the meaningfulness of differentiating not only between direct and indirect aggression but also between direct and indirect victimization. Boys reported being more victim to direct aggression, whereas girls reported being more victim to indirect aggression. Direct aggression predicted increased conduct problems in boys, whereas indirect aggression predicted increased conduct problems in girls, and conduct problems reciprocally predicted increased direct and indirect aggression. Indirect victimization showed prospective bidirectional associations with emotional symptoms and conduct problems, suggesting the potential development of vicious cycles of escalating problems in these areas.
  
  
  CONCLUSIONS
  The present results indicate that direct and indirect aggression, as well as direct and indirect victimization, may have different roles in the development of psychological difficulties in young adolescents. Further, the demonstration of prospective bidirectional associations points to a possible mechanism for the development of psychological difficulties, that may be described in terms of dynamical systems theory. This has potential relevance both for the prevention and the treatment of psychopathology.
authors.affiliation: Department of Psychology, Lund University, Box 213, 221 00 Lund, Sweden.
authors.forename: Lars-Gunnar
authors.initials: LG
authors.lastname: Lundh
authors.affiliation: Department of Psychology, Lund University, Box 213, 221 00 Lund, Sweden.
authors.forename: Daiva
authors.initials: D
authors.lastname: Daukantaité
authors.affiliation: Department of Psychology, Lund University, Box 213, 221 00 Lund, Sweden.
authors.forename: Margit
authors.initials: M
authors.lastname: Wångby-Lundh
keywords: Bidirectional associations; Conduct problems; Direct aggression; Direct victimization; Emotional problems; Indirect aggression; Indirect victimization; Longitudinal design