title: Gender differences in the associations among marijuana use, cigarette use, and symptoms of depression during adolescence and young adulthood.
abstract: BACKGROUND
  As prevalence of marijuana use increases, it is important that we better understand how factors like gender, cigarette use, and depression are related to marijuana use during adolescence and young adulthood. We examined longitudinal relationships among these variables in adolescents moving into young adulthood who were studied longitudinally for six years.
  
  
  METHODS
  1263 individuals were included in the study. Participants were oversampled for ever-smoking a cigarette at baseline, when they were 15-16 years old. Frequency of cigarette smoking and marijuana use, as well as depression symptoms, were assessed at baseline, 6, 15, 24, 60 and 72 months.
  
  
  RESULTS
  Cigarette use frequency and depression symptoms were associated with frequency of marijuana use (p-values<.001), particularly in adolescence, but there were important gender differences in these relationships. Specifically, symptoms of depression were related to marijuana use frequency among males (p<.001), but not females (p=.62). In addition, frequency of marijuana use was associated with increased cigarette use frequency, especially among males who had higher symptoms of depression (p<.001). However, this effect was not seen among females. Exploratory analyses suggested that relationships between frequency of use and depression are specific to marijuana, not cigarettes.
  
  
  CONCLUSIONS
  Marijuana use is strongly related to depression symptoms and cigarette use frequency in males, indicating that in males these detrimental factors converge, whereas in females they do not. Gender differences in the factors related to marijuana use may mean that there are different risks for and consequences from use and have implications for prevention and intervention efforts.
authors.affiliation: Department of Psychology, University of Illinois at Chicago, 1007 West Harrison Street (M/C 285), Chicago, IL 60607, United States; Department of Psychiatry, University of Illinois at Chicago, 1601 West Taylor Street (M/C 912), Chicago, IL 60612, United States; Center for Cognitive Neuroscience, University of Illinois at Chicago, 1601 West Taylor Street (M/C 912), Chicago, IL 60612, United States; Institute for Health Research and Policy, University of Illinois at Chicago, 1747 West Roosevelt Road (M/C 275), Chicago, IL 60608, United States. Electronic address: ncrane3@uic.edu.
authors.forename: Natania A
authors.initials: NA
authors.lastname: Crane
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, 1601 West Taylor Street (M/C 912), Chicago, IL 60612, United States; Center for Cognitive Neuroscience, University of Illinois at Chicago, 1601 West Taylor Street (M/C 912), Chicago, IL 60612, United States.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Langenecker
authors.affiliation: Department of Psychology, University of Illinois at Chicago, 1007 West Harrison Street (M/C 285), Chicago, IL 60607, United States; Institute for Health Research and Policy, University of Illinois at Chicago, 1747 West Roosevelt Road (M/C 275), Chicago, IL 60608, United States.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Mermelstein
mesh_terms: D000293:Adolescent; D015331:Cohort Studies; D003863:Depression / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology* / Q000523:psychology; D011446:Prospective Studies; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Cigarettes; Depression; Gender; Marijuana; Nicotine; Sex differences