title: Patterns of the co-use of alcohol, marijuana, and emerging tobacco products in a national sample of young adults.
abstract: BACKGROUND
  Emerging tobacco product use is on the rise in young adults and has been linked to alcohol and marijuana use. Little is known about which patterns of alcohol, marijuana, and emerging tobacco product co-use are most popular in this age group.
  
  
  OBJECTIVE
  This study examined the prevalence of a broad spectrum of marijuana, alcohol, and tobacco co-use patterns across a variety of tobacco products in a national sample of young adults.
  
  
  METHODS
  Data were analyzed from a sub-set of 18-24 year olds (unweighted n = 3,940) from five waves of the Truth Initiative Young Adult Cohort, a national sample of 18-34 year olds. A user-generated statistical program in R was used to assess all possible patterns of past 30-day use of alcohol, marijuana, cigarettes, cigars, e-cigarettes, little cigars/cigarillos, hookah, and other tobacco (pipe, chew, dip, snus, dissolvables).
  
  
  RESULTS
  No past 30-day use of any substance emerged as the most popular pattern across all years (42%), followed by exclusive past 30-day alcohol use (31%), and past 30-day alcohol use with cigarettes (5%) or marijuana (4%). The popularity of exclusive marijuana use increased over time, but only 1% reported exclusive marijuana use without the combination of either alcohol or a tobacco product. E-cigarette use only emerged in combination with alcohol and was the least popular pattern of co-use relative to other patterns.
  
  
  CONCLUSIONS
  Patterns stress the importance of alcohol among young people. Successful substance use prevention should focus on alcohol's co-use with a variety of substances of abuse, rather than focus on a single behavior. (Am J Addict 2016;25:634-640).
authors.affiliation: The Schroeder Institute for Tobacco Research and Policy Studies at Truth Initiative, Washington, District of Columbia.|Department of Oncology, Georgetown University Medical Center, Cancer Prevention and Control Program, Georgetown Lombardi Comprehensive Cancer Center, Washington, District of Columbia.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Cohn
authors.affiliation: The Schroeder Institute for Tobacco Research and Policy Studies at Truth Initiative, Washington, District of Columbia.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Johnson
authors.affiliation: Department of Evaluation Science and Research at Truth Initiative, Washington, District of Columbia.|Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Rath
authors.affiliation: The Schroeder Institute for Tobacco Research and Policy Studies at Truth Initiative, Washington, District of Columbia.|Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Andrea C
authors.initials: AC
authors.lastname: Villanti