title: Momentary positive and negative affect preceding marijuana use events in youth.
abstract: ABSTRACT. among young people. This study examined how positive and negative affect differ before marijuana use compared with other times.
  
  
  METHODS
  Forty medical outpatients ages 15-24 years who used marijuana recreationally at least twice a week (M = 18.7 years; 58% female) reported momentary positive affect, negative affect, companionship, perceived ease of obtaining marijuana, and marijuana use several times a day for 2 weeks on a handheld computer. Mean momentary positive affect and negative affect scores in the 24 hours leading up to a marijuana use event (n = 294) were compared with affect scores in times further from subsequent use. Generalized estimating equation models considered as potential moderators perceived ease of obtaining marijuana and being with friends.
  
  
  RESULTS
  Positive affect did not differ in the 24 hours before marijuana use compared with times further before use. Negative affect was significantly higher before marijuana use compared with other times. Being with friends and perceived easy marijuana availability did not moderate the associations. The association between negative affect and subsequent marijuana use was attenuated when negative affect was examined only for the moment just before use, suggesting that use may follow a period of increased negative affect.
  
  
  CONCLUSIONS
  The findings support an affect regulation model for marijuana use among frequently using youth. Specifically, these youth may use marijuana to manage increased negative affect.
authors.affiliation: Division of Adolescent/Young Adult Medicine, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: Lydia A
authors.initials: LA
authors.lastname: Shrier
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts.
authors.forename: Craig S
authors.initials: CS
authors.lastname: Ross
authors.affiliation: Clinical Research Center, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: Emily A
authors.initials: EA
authors.lastname: Blood
mesh_terms: D000293:Adolescent; D000339:Affect; D034201:Computers, Handheld / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology / Q000523:psychology*; D009042:Motivation; D057566:Self Report; D055815:Young Adult