title: Brief report: Growth in polysubstance use among youth in the child welfare system.
abstract: OBJECTIVE
  This paper establishes foundational knowledge on development of polysubstance use among adolescents in the U.S. child welfare system (CWS).
  
  
  METHODS
  Data on U.S. CWS adolescents from the National Study of Child and Adolescent Well-Being were examined for rates of alcohol, marijuana, and hard drug use; and change in use over time.
  
  
  RESULTS
  Past 30-day absolute use was highest for alcohol, but daily/near-daily use highest for marijuana. Marijuana use increased at later time points. A correlated growth model suggested covariation in use of the substances. A curve-of-factors model suggested that higher-order factors explain most variation in substance use, except at the last time point. Those with lower use changed the most across time.
  
  
  CONCLUSIONS
  Subsequent research among CWS adolescents in the U.S. should consider substances jointly. Prevention should focus on marijuana, and later periods of adolescence and CWS involvement. Youth not thought of as at great risk upon entering the CWS may be most vulnerable.
authors.affiliation: American Institutes for Research, 1000 Thomas Jefferson St., NW, Office 3263, Washington, DC 20007-3835, United States. Electronic address: lyarnell@air.org.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Yarnell
authors.affiliation: School of Social Work, University of Southern California, 669 W. 34th St., Los Angeles, CA 90089-0411, United States. Electronic address: traube@usc.edu.
authors.forename: Dorian E
authors.initials: DE
authors.lastname: Traube
authors.affiliation: School of Social Work, University of Southern California, 669 W. 34th St., Los Angeles, CA 90089-0411, United States; Division of Hospital Medicine, Children's Hospital Los Angeles, 4650 Sunset Blvd, MS #94, Los Angeles, CA 90027, United States. Electronic address: sschrager@chla.usc.edu.
authors.forename: Sheree M
authors.initials: SM
authors.lastname: Schrager
mesh_terms: D000293:Adolescent; D002648:Child; D002669:Child Welfare; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology / Q000639:trends*; D012307:Risk Factors; D015813:Substance Abuse Detection; D019966:Substance-Related Disorders / Q000453:epidemiology*; D000066608:Underage Drinking / Q000706:statistics & numerical data / Q000639:trends*; D014481:United States / Q000453:epidemiology
keywords: Child welfare; Latent growth modeling; Substance use