title: What is positive youth development and how might it reduce substance use and violence? A systematic review and synthesis of theoretical literature.
abstract: BACKGROUND
  Preventing adolescent substance use and youth violence are public health priorities. Positive youth development interventions are widely deployed often with the aim of preventing both. However, the theorised mechanisms by which PYD is intended to reduce substance use and violence are not clear and existing evaluated interventions are under-theorised. Using innovative methods, we systematically searched for and synthesised published theoretical literature describing what is meant by positive youth development and how it might reduce substance use and violence, as part of a broader systematic review examining process and outcomes of PYD interventions.
  
  
  METHODS
  We searched 19 electronic databases, review topic websites, and contacted experts between October 2013 and January 2014. We included studies written in English, published since 1985 that reported a theory of change for positive youth development focused on prevention of smoking, alcohol consumption, drug use or violence in out-of-school settings. Studies were independently coded and quality-assessed by two reviewers.
  
  
  RESULTS
  We identified 16 studies that met our inclusion criteria. Our synthesis suggests that positive youth development aims to provide youth with affective relationships and diverse experiences which enable their development of intentional self-regulation and multiple positive assets. These in turn buffer against or compensate for involvement in substance use and violence. Existing literature is not clear on how intentional self-regulation is developed and which specific positive assets buffer against substance use or violence.
  
  
  CONCLUSIONS
  Our synthesis provides: an example of a rigorous systematic synthesis of theory literature innovatively applying methods of qualitative synthesis to theoretical literature; a clearer understanding of how PYD might reduce substance use and violence to inform future interventions and empirical evaluations.
authors: Department of Childhood, Families and Health, University College London Institute of Education, 18 Woburn Square, WC1H 0NR, London, UK. c.bonell@ioe.ac.uk.
authors: Chris
authors: C
authors: Bonell
authors: Department of Childhood, Families and Health, University College London Institute of Education, 18 Woburn Square, WC1H 0NR, London, UK.
authors: Kate
authors: K
authors: Hinds
authors: Department of Childhood, Families and Health, University College London Institute of Education, 18 Woburn Square, WC1H 0NR, London, UK.
authors: Kelly
authors: K
authors: Dickson
authors: Department of Childhood, Families and Health, University College London Institute of Education, 18 Woburn Square, WC1H 0NR, London, UK.
authors: James
authors: J
authors: Thomas
authors: Cardiff School of Social Sciences, Cardiff University, CF10 3BD, Cardiff, UK.
authors: Adam
authors: A
authors: Fletcher
authors: Cardiff School of Social Sciences, Cardiff University, CF10 3BD, Cardiff, UK.
authors: Simon
authors: S
authors: Murphy
authors: Division of Health Sciences, Warwick Medical School, University of Warwick, CV4 7AL, Coventry, UK.
authors: G J
authors: GJ
authors: Melendez-Torres
authors: Forest School, 2 College Place, E17 3PY, London, UK.
authors: Carys
authors: C
authors: Bonell
authors: School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, BS8 2PS, Bristol, UK.
authors: Rona
authors: R
authors: Campbell
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D006801:Humans; D012907:Smoking / Q000453:epidemiology; D000074606:Smoking Prevention; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000517:prevention & control*; D014754:Violence / Q000517:prevention & control* / Q000706:statistics & numerical data