title: Tobacco and marijuana use among adolescents and young adults: a systematic review of their co-use.
abstract: Tobacco (TOB) and marijuana (MJ) are the most widely used drugs among adolescents and young adults. The literature on their co-use, however, has not been systematically reviewed. We identified 163 English language articles published from 1999 to 2009 examining TOB and MJ co-use, correlates or consequences of co-use, or interventions for prevention or cessation of co-use with participants aging 13-25 years. Most studies (n=114, 70%) examined TOB and MJ co-use, and 85% of relationships studied indicated a significant association. Fifty-nine studies (36%) examined correlates or consequences of co-use. Factors consistently associated with increased likelihood of co-use, defined as significant associations in at least four studies, were African-American ethnicity, mental and physical health characteristics (e.g., high-intensity pleasure temperament), and school characteristics (e.g., good grades). The only consistent consequence of co-use was exacerbation of mental health symptoms. Few studies examined prevention (n=3) or cessation (n=2) interventions for TOB and MJ co-use, and the findings were stronger for prevention efforts. A sufficient literature base has documented that TOB and MJ use are strongly related in young people, yet few consistent correlates and consequences of co-use have been identified to inform intervention targets.
authors.affiliation: Department of Psychiatry, University of California, San Francisco, 401 Parnassus Avenue, Box TRC 0984, San Francisco, CA 94114, USA. danielle.ramo@ucsf.edu
authors.forename: Danielle E
authors.initials: DE
authors.lastname: Ramo
authors.forename: Howard
authors.initials: H
authors.lastname: Liu
authors.forename: Judith J
authors.initials: JJ
authors.lastname: Prochaska
mesh_terms: D000293:Adolescent; D000328:Adult; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology*; D012574:Schools; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation