title: Benefits of universal intervention effects on a youth protective shield 10 years after baseline.
abstract: OBJECTIVE
  An earlier randomized controlled study found that a universal, family-focused preventive intervention produced protective shield effects-reduced adolescent exposures to illicit substance opportunities-among adolescents in grade 12. This study examined a follow-up assessment of the sample during young adulthood.
  
  
  METHODS
  A randomized controlled trial evaluated the Iowa Strengthening Families Program that was implemented in 22 rural schools (N = 446 families) when the participants were in grade six. Measures included adolescent exposure to illicit substance use and young adult lifetime substance use (age 21; N = 331). Growth curve modeling examined indirect intervention effects through growth factors of adolescent exposure.
  
  
  RESULTS
  Findings from this study confirm protective shield effects that mediate long-term reduction of illicit substance use (β = -.14, p = .02, Relative Reduction Rate = 28.2%).
  
  
  CONCLUSIONS
  The benefits of decreasing exposure to substance use during adolescence through universal interventions were supported, with positive effects extending into young adulthood.
authors.affiliation: Partnerships in Prevention Science Institute, Iowa State University, Ames, IA, USA. rlspoth@iastate.edu
authors.forename: Richard L
authors.initials: RL
authors.lastname: Spoth
authors.forename: Linda S
authors.initials: LS
authors.lastname: Trudeau
authors.forename: Max
authors.initials: M
authors.lastname: Guyll
authors.forename: Chungyeol
authors.initials: C
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D000367:Age Factors; D005196:Family Therapy / Q000379:methods*; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D015233:Models, Statistical; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000517:prevention & control*; D013997:Time Factors; D055815:Young Adult