title: Programs for Prevention of Externalizing Problems in Children: Limited Evidence for Effect Beyond 6 Months Post Intervention.
abstract: BACKGROUND
  Preventing externalizing problems in children is a major societal concern, and a great number of intervention programs have been developed to this aim. To evaluate their preventive effects, well-controlled trials including follow-up assessments are necessary.
  
  
  METHODS
  This is a systematic review of the effect of prevention programs targeting externalizing problems in children. The review covered peer reviewed publications in English, German, French, Spanish and Scandinavian languages. Experimental studies of standardized programs explicitly aiming at preventing externalizing mental ill-health in children (2-19 years), with outcome assessments at ≥6 months post intervention for both intervention and control groups, were included. We also included long-term trials with consecutive observations over several years, even in the absence of follow-up ≥6 months post intervention. Studies of clinical populations or children with impairments, which substantially increase the risk for mental disorders, were excluded.
  
  
  RESULTS
  Thirty-eight controlled trials assessing 25 different programs met inclusion criteria. Only five programs were supported by scientific evidence, representing selective parent training (Incredible Years and Triple-P), indicated family support (Family Check-Up), and school-based programs (Good Behavior Game, universally delivered, and Coping Power, as an indicated intervention). With few exceptions, effects after 6-12 months were small. Long-term trials showed small and inconsistent effects.
  
  
  CONCLUSIONS
  Despite a vast literature, the evidence for preventive effects is meager, largely due to insufficient follow-up post intervention. Long-term follow up assessment and effectiveness studies should be given priority in future evaluations of interventions to prevent externalizing problems in children.
authors.affiliation: Department of Psychology, Stockholm University, 10691 Stockholm, Sweden.
authors.forename: Ann-Charlotte
authors.initials: AC
authors.lastname: Smedler
authors.affiliation: Centre for Health Equity Studies (CHESS), Stockholm University/Karolinska Institutet, Stockholm, Sweden ; Clinical Epidemiology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Hjern
authors.affiliation: Department of Social Work, Stockholm University, Stockholm, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wiklund
authors.affiliation: The Swedish Council on Health Technology Assessment, Stockholm, Sweden.
authors.forename: Sten
authors.initials: S
authors.lastname: Anttila
authors.affiliation: The Swedish Council on Health Technology Assessment, Stockholm, Sweden ; LIME, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Agneta
authors.initials: A
authors.lastname: Pettersson
keywords: Child; Externalizing; Mental health; Meta-analysis; Prevention