title: Mapping risk factors for substance use: Introducing the YouthMap12.
abstract: In adolescence, psychological problems and regular use of alcohol, cigarettes, cannabis and other drugs (AOD) tend to cluster together, strongly indicating that certain groups of young people are at elevated risk of developing a problematic use of AOD.
  
  
  
  The aim of the present study was to develop an easy-to-implement screening instrument to identify subgroups of young people with different psychological problems at risk of problem use of AOD.
  
  
  
  3589 randomly selected young Danes between 15 and 25years of age, from a national survey (n=2702) and a municipality survey (n=887), answered a 12-item questionnaire (YouthMap12) with 6 items identifying externalizing problems (EP6) and 6 items identifying internalizing problems (IP6). Latent class analysis (LCA) was used to characterize groups at risk, and associations were estimated between EP6 and IP6 and regular use of AOD, and between latent class membership and regular use of AOD.
  
  
  
  LCA identified 6 classes with varying degrees of externalizing and internalizing problems: 70% of youth were in the low problem score class, and the remaining 30% were at various levels of risk. Regular use of cigarettes, cannabis and alcohol was strongly associated with classes characterized by externalizing problems, while over-the-counter and prescription medicine was strongly associated with classes characterized by internalizing problems.
  
  
  
  Youth at risk of problem use of AOD can be identified using a simple and easily administered instrument.
authors.affiliation: Centre for Alcohol and Drug Research, School of Business and Social Sciences, Aarhus University, Denmark. Electronic address: mup.crf@psy.au.dk.
authors.forename: Mads Uffe
authors.initials: MU
authors.lastname: Pedersen
authors.affiliation: Centre for Alcohol and Drug Research, School of Business and Social Sciences, Aarhus University, Denmark.
authors.forename: Kristine
authors.initials: K
authors.lastname: Rømer Thomsen
authors.affiliation: Centre for Alcohol and Drug Research, School of Business and Social Sciences, Aarhus University, Denmark.
authors.forename: Michael Mulbjerg
authors.initials: MM
authors.lastname: Pedersen
authors.affiliation: Centre for Alcohol and Drug Research, School of Business and Social Sciences, Aarhus University, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Hesse
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D007389:Internal-External Control; D008297:Male; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000523:psychology*; D011795:Surveys and Questionnaires
keywords: Adolescents; Externalizing; Integrative approaches; Internalizing; Latent class analysis; Substance use