title: Time-varying associations between confidence and motivation to abstain from marijuana during treatment among adolescents.
abstract: BACKGROUND
  An important goal of addictions treatment is to develop a positive association between high levels of confidence and motivation to abstain from substance use. This study modeled the time-varying association between confidence and motivation to abstain from marijuana use among youth in treatment, and the time-varying effect of pre-treatment covariates (marijuana abstinence goal and perceived peer marijuana use) on motivation to abstain.
  
  
  METHODS
  150 adolescents (75% male, 83% White) in community-based intensive outpatient treatment in Pennsylvania completed a pre-treatment assessment of abstinence goal, perceived peer marijuana use, and motivation and confidence to abstain from marijuana. Ratings of motivation and confidence to abstain also were collected after each session. A time-varying effect model (TVEM) was used to characterize changes in the association between confidence and motivation to abstain (lagged), and included covariates representing pre-treatment abstinence goal and perceived peer marijuana use.
  
  
  RESULTS
  Confidence and motivation to abstain from marijuana generally increased during treatment. The association between confidence and motivation strengthened across sessions 1-4, and was maintained through later sessions. Pre-treatment abstinence goal had an early time-limited effect (through session 6) on motivation to abstain. Pre-treatment perception of peer marijuana use had a significant effect on motivation to abstain only at session 2.
  
  
  CONCLUSIONS
  Early treatment sessions represent a critical period during which the association between confidence and motivation to abstain generally increased. The time-limited effects of pre-treatment characteristics suggest the importance of early sessions in addressing abstinence goal and peer substance use that may impact motivation to abstain from marijuana.
authors.affiliation: University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA 15213, United States. Electronic address: chungta@upmc.edu.
authors.forename: Tammy
authors.initials: T
authors.lastname: Chung
authors.affiliation: Syracuse University, Department of Psychology, Syracuse, NY 13244, United States.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Maisto
mesh_terms: D000293:Adolescent; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000517:prevention & control* / Q000523:psychology; D008385:Marijuana Smoking / Q000517:prevention & control* / Q000523:psychology; D009042:Motivation; D000067074:Peer Influence; D020377:Self Efficacy; D013997:Time Factors
keywords: Adolescent; Marijuana use; Motivation to abstain; Self-efficacy; Time-varying effect model; Treatment