title: A quasi-randomized group trial of a brief alcohol intervention on risky single occasion drinking among secondary school students.
abstract: OBJECTIVE
  To show the effectiveness of a brief group alcohol intervention. Aims of the intervention were to reduce the frequency of heavy drinking occasions, maximum number of drinks on an occasion and overall weekly consumption.
  
  
  METHODS
  A cluster quasi-randomized control trial (intervention n = 338; control n = 330) among 16- to 18-year-old secondary school students in the Swiss Canton of Zürich. Groups homogeneous for heavy drinking occasions (5+/4+ drinks for men/women) consisted of those having medium risk (3-4) or high risk (5+) occasions in the past 30 days. Groups of 8-10 individuals received two 45-min sessions based on motivational interviewing techniques.
  
  
  RESULTS
  Borderline significant beneficial effects (p < 0.10) on heavy drinking occasions and alcohol volume were found 6 months later for the medium-risk group only, but not for the high-risk group. None of the effects remained significant after Bonferroni corrections.
  
  
  CONCLUSIONS
  Group intervention was ineffective for all at-risk users. The heaviest drinkers may need more intensive treatment. Alternative explanations were iatrogenic effects among the heaviest drinkers, assessment reactivity, or reduction of social desirability bias at follow-up through peer feedback.
authors.affiliation: Research Department, Addiction Switzerland, Avenue de Ruchonnet 14, P.O. Box 870, 1001 Lausanne, Switzerland. ggmel@addictionsuisse.ch
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gmel
authors.forename: Vigeli
authors.initials: V
authors.lastname: Venzin
authors.forename: Katrin
authors.initials: K
authors.lastname: Marmet
authors.forename: George
authors.initials: G
authors.lastname: Danko
authors.forename: Florian
authors.initials: F
authors.lastname: Labhart
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking / Q000517:prevention & control*; D000435:Alcoholic Intoxication / Q000517:prevention & control*; D005260:Female; D006126:Group Processes; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D008297:Male; D009042:Motivation; D017063:Outcome Assessment, Health Care; D015397:Program Evaluation; D012307:Risk Factors; D012574:Schools; D013334:Students; D013557:Switzerland; D055815:Young Adult