title: Cost-Effectiveness of School-Based Prevention of Cannabis Use.
abstract: BACKGROUND
  Cannabis is the most frequently used illicit drug globally. Despite increasing evidence that cannabis use is associated with adverse health effects, the knowledge on preventative strategies is still limited. This study stemmed from a systematic review of effective prevention in which school-based programmes were identified as promising. The primary objective was to evaluate the cost effectiveness of Project ALERT (Adolescent, Learning, Experiences, Resistance, and Training), compared with ordinary ATOD (Alcohol, Tobacco, and Other Drug) education, among Swedish students in the eighth grade of compulsory school.
  
  
  METHODS
  The cost-effectiveness analysis was performed from the societal perspective with quality-adjusted life-years (QALYs) as an outcome (willingness-to-pay threshold €50,000) and follow-up periods from 1 year to a lifetime, considering a discounting rate of 3%, and with costs inflated to 2013 levels. A Markov model was constructed on the basis of the 'states' of single use, regular use, daily use and use of other illicit drugs, which were associated with 'complications' of psychosis, schizophrenia, traffic accidents, depression and amotivational syndrome. Health and cost consequences were linked to both states and complications.
  
  
  RESULTS
  The programme was cost saving on the basis of evidence from the USA (ratio 1:1.1), and was cost effective (incremental cost-effectiveness ratio €22,384 per QALY) after reasonable adjustment for the Swedish context and with 20 years of follow-up. When the target group was restricted to boys who were neither studying nor working/doing work experience, the programme was cost effective after 9 years and cost saving (ratio 1:3.2) after 20 years.
  
  
  CONCLUSIONS
  School-based prevention such as Project ALERT has the potential to be cost effective and to be cost saving if implemented in deprived areas. In the light of the shifting landscape regarding legalization of cannabis, it seems rational to continue the health economic analysis of prevention initiated here.
authors.affiliation: Karolinska Institutet, Public Health Sciences, 177 77, Stockholm, Sweden.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Deogan
authors.affiliation: Dental and Pharmaceutical Benefits Agency, Stockholm, Sweden.
authors.forename: Natalie
authors.initials: N
authors.lastname: Zarabi
authors.affiliation: National Board of Health and Welfare, Stockholm, Sweden.
authors.forename: Nils
authors.initials: N
authors.lastname: Stenström
authors.affiliation: Public Health Agency of Sweden, Stockholm, Sweden.
authors.forename: Pi
authors.initials: P
authors.lastname: Högberg
authors.affiliation: Karolinska Institutet, Public Health Sciences, 177 77, Stockholm, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Skärstrand
authors.affiliation: Karolinska Institutet, Public Health Sciences, 177 77, Stockholm, Sweden.
authors.forename: Edison
authors.initials: E
authors.lastname: Manrique-Garcia
authors.affiliation: Aux Analysis AB, Stockholm, Sweden.
authors.forename: Kristian
authors.initials: K
authors.lastname: Neovius
authors.affiliation: Karolinska Institutet, Public Health Sciences, 177 77, Stockholm, Sweden. anna.mansdotter@ki.se.
authors.forename: Anna
authors.identifier: http://orcid.org/0000-0003-2246-2065
authors.initials: A
authors.lastname: Månsdotter
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003362:Cost-Benefit Analysis; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000150:complications / Q000191:economics / Q000453:epidemiology / Q000517:prevention & control*; D008875:Middle Aged; D018803:Models, Economic; D019057:Quality-Adjusted Life Years; D012572:School Health Services / Q000191:economics*; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult