title: Associations of adolescent cannabis use with academic performance and mental health: A longitudinal study of upper middle class youth.
abstract: BACKGROUND
  There is a hypothesis that low socioeconomic status (SES) may explain the link between cannabis use and poorer academic performance and mental health. A key question, therefore, is whether adolescent cannabis use is associated with poorer academic performance and mental health in high SES communities where there is reduced potential for confounding.
  
  
  METHODS
  Youth (n=254) from an upper middle class community were followed prospectively through the four years of high school (from age 14/15 to age 17/18). Past-year frequency of cannabis use was assessed annually. Official school records of academic performance and self-reported mental health symptoms (externalizing and internalizing symptoms) were assessed in grades 9 and 12.
  
  
  RESULTS
  Persistent cannabis use across the four years of high school was associated with lower grade-point average (β=-0.18, p=.006), lower Scholastic Aptitude Test (SAT) score (β=-0.13, p=.038), and greater externalizing symptoms (β=0.29, p<.001) in 12th grade, but not with greater internalizing symptoms (β=0.04, p=.53). Moreover, persistent cannabis use was associated with lower grade-point average (β=-0.13, p=.014) and greater externalizing symptoms (β=0.24, p=.002) in 12th grade, even after controlling for 9th grade levels of these outcomes. Similar associations were observed for persistent alcohol and tobacco use. Effects for persistent cannabis use became non-significant after controlling for persistent alcohol and tobacco use, reflecting the difficulties of disentangling effects of cannabis from effects of alcohol and tobacco.
  
  
  CONCLUSIONS
  Low SES cannot fully explain associations between cannabis use and poorer academic performance and mental health.
authors.affiliation: Department of Psychology, Arizona State University, PO Box 871104, Tempe, AZ 85287-1104, USA. Electronic address: madeline.meier@asu.edu.
authors.forename: Madeline H
authors.initials: MH
authors.lastname: Meier
authors.affiliation: Department of Psychology, Arizona State University, PO Box 871104, Tempe, AZ 85287-1104, USA.
authors.forename: Melanie L
authors.initials: ML
authors.lastname: Hill
authors.affiliation: Department of Psychology, Arizona State University, PO Box 871104, Tempe, AZ 85287-1104, USA.
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Small
authors.affiliation: Department of Psychology, Arizona State University, PO Box 871104, Tempe, AZ 85287-1104, USA.
authors.forename: Suniya S
authors.initials: SS
authors.lastname: Luthar
mesh_terms: D000293:Adolescent; D000428:Alcohol Drinking / Q000523:psychology; D001077:Aptitude Tests; D004522:Educational Status; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology* / Q000523:psychology*; D008603:Mental Health; D011446:Prospective Studies; D012737:Sex Factors; D012923:Social Class; D064424:Tobacco Use / Q000523:psychology
keywords: Adolescent; Cannabis; Grade-point average; Longitudinal; Mental health; SES