Date of Award

Spring 6-8-2017

Document Type


Degree Name

Doctor of Philosophy in Clinical Psychology (PhD)


Clinical Psychology

First Advisor/Committee Member

David G. Stewart

Second Advisor/Committee Member

Amy Mezulis

Third Advisor/Committee Member

Jennifer Harris


The purpose of this study was to investigate the utility of text coaching on reducing substance use in adolescents participating in a school-based manualized intervention that utilizes Motivational Interviewing (MI) and motivational enhancement principles. A further aim of this study was to examine how perceived treatment satisfaction and self-efficacy mediate this relationship. Participants included 76 adolescents (62% male, 65% ethnic minority), ages 14-19 (M = 16), referred for substance use assessment and intervention by school administrators at large suburban public high schools. It was hypothesized that individuals who received the addition of text coaching would evidence a greater reduction in substance use compared to individuals who did not receive text coaching by the end of treatment and at post-treatment follow-up. Data was collected via an online survey tool. Substance use was measured using the Customary Drinking and Drug Use Record (Brown, et al., 1998). Treatment satisfaction was measured using the What I Got from Treatment scale (Miller & Brown, 1994). Self-efficacy was measured using the Situational Confidence Questionnaire (Annis & Graham, 1988). Multiple regression analyses were conducted for alcohol use and marijuana use separately. Text coaching predicted greater reduction in alcohol use at end of treatment (R2 = .11, F = 4.08 [2, 67], p < .05), but not marijuana use (R2 = .04, F = 1.49 [2, 67], p = .233). Text coaching as a predictor of greater reduction in alcohol use at post-treatment follow-up was trending towards significance (R2 = .06, F = 2.70 [2, 48], p = .078); however, not for marijuana use (R2 = .05, F = 1.11 [2, 46], p = .337). Additionally, PROCESS Macro for SPSS 22 (Hayes, 2013) was used to determine the mediating effects of treatment satisfaction and self-efficacy. This mediation analysis failed to reach significance on any pathway. These results indicated text coaching was an effective adjunct intervention in decreasing alcohol use in high-risk substance using adolescence. This study provides a rationale for designing substance use interventions for adolescents with a text coaching component as a means of enhancing the gains made from treatment.

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