Date of Award


Document type


Access Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

School Psychology

First Advisor

John M. Hintze

Second Advisor

William J. Matthews

Third Advisor

Elizabeth A. Harvey

Subject Categories

Education | Educational Psychology | Student Counseling and Personnel Services


Substance abuse is the foremost health problem in the United States, with an estimated annual cost of over $400 billion and is linked to over 400,000 preventable deaths each year. Adolescents are among those abusing drugs and alcohol. Approximately one-half of high school students use alcohol and one-fourth smoke marijuana, and by their senior year of high school, over half will have used an illicit drug. Effective substance use interventions for young adults are important in preventing the progression toward other drug use disorders and harmful consequences of frequent drug use. Schools have been identified as a viable setting in which to conduct brief interventions to reduce adolescent substance use. However, a standard therapy for implementing motivational interventions in the school setting has not yet been established. The purpose of this study was to investigate the efficacy of a motivational intervention on substance use in a school-based adolescent population and to test the hypotheses that motivational interviewing, compared to assessment only, would result in a reduction of substance use and an increase in each participant's readiness to change. The proposed study utilized a randomized controlled design in which participants received one of two conditions, two 30-minute sessions of a motivational intervention or assessment only. Assessments were administered before and one month following the intervention. Results demonstrated that the intervention was effective in reducing daily cigarette use and symptoms of cigarette dependence for participants in the experimental group. These results are consistent with past research investigating the effectiveness of motivational interventions on reducing adolescent substance use, yet the current findings are unique because this is the first school-based motivational intervention delivered by school personnel to effectively reduce adolescent substance use. Results indicate that the current intervention could be implemented as a standard therapy for using motivational interventions to decrease adolescent substance use in the school setting.