Psychology ETDs

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There is support in the literature for motivational enhancement therapy (MET) as an acceptable method for achieving abstinence and increasing retention in therapy for the treatment of marijuana and alcohol abuse, and for contingency management (CM) as a useful tool for enhancing both of these objectives when combined with empirically supported therapies such as MET. However, MET combined with CM had yet to be tested with substance using adolescents and young adults enrolled in a substance use program in a vocational and educational training facility. This study examined the effectiveness of an MET and CM program designed to provide opportunities to win prizes to reinforce therapy attendance and submission of urine samples that were negative for marijuana. Fourteen (N=14) individuals from a vocational training center who tested positive for marijuana on their initial drug screen were assigned to receive either standard treatment (ST), or CM plus MET in addition to ST. The retention rates of twenty-two (N=22) non-randomized participants who had tested positive for marijuana upon entry to the training center were also compared to the retention rates of the study participants. The MET+CM+ST group demonstrated significantly higher study drug screen pass rates at 1- and 3-month follow-ups, and significantly greater percent days abstinent (PDA) for marijuana at the 3-month follow-up compared to the ST group. In addition, the percentage of trainees who successfully passed their second official drug screen and were therefore retained and able to continue their training at the Job Corps was significantly higher for those who consented into the study than the non-randomized participant group; however, there were no statistical differences found between the study groups in retention, largely due to administrative leniency extended to the ST group by the training program. Originally, incoming trainees who were on probation for alcohol use were to be included in the study as well, however none of the incoming trainees were on probation due to alcohol use during the duration of this study. Also, there was very little alcohol use reported by the participants who were enrolled in the study, and there were no significant findings regarding alcohol use. The study results build upon prior research and offer an initial exploratory analysis of the efficacy of MET and CM with trainees from a vocational program who tested positive for marijuana, and highlights recommendations for developing interventions to facilitate abstinence in a real life, non-clinical setting.

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First Advisor

McCrady, Barbara

First Committee Member (Chair)

Goldsmith, Timothy

Second Committee Member

Smith, Jane Ellen

Third Committee Member

Woodall, Gill




Marijuana abuse--treatment, Behavior therapy, Achievement motivation in youth, Vocational school students--Psychology.

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